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• Troubleshooting Website problems within the local network

  - by HaydnWVN

  Have an external website which opens fine on some PC's, yet seems to time out (or symptoms of timing out, but never actually does) on others. Seems to only affect (some) of our newer HP Pro 3305 MT Workstations. All of which are running Win7 32bit SP1 with all updates. Older PC's (Win7 32bit SP1 & WinXP) are unaffected. Using Google Chrome & Firefox makes no difference. Opening the website in IE9 Compatibility Mode has exactly the same symptoms. All PC's are on the same local network (Workgroup) using the same DNS server & gateway (inhouse) on the same internet connection, on the same subnet. There is no proxy server, no content filtering, no load balancing etc etc. Only group policy in effect (locally) is for Update scheduling. Local firewalls are all the same (Kaspersky WP4) and our external facing firewall has no IP specific settings. I have no control over the external website, traceroute shows the same destination on all PC's. It is a fairly popular website in our industry (Horticulture) and i'm not aware of any other people (even other sites within our sister companies) with the same problem. Update: Used Fiddler2 to monitor the HTTP request, seems its not getting fulfilled for some reason?! Request sent: GET http://www.rhs.org.uk/ HTTP/1.1 Host: www.rhs.org.uk Connection: keep-alive User-Agent: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/536.11 (KHTML, like Gecko) Chrome/20.0.1132.47 Safari/536.11 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-GB,en-US;q=0.8,en;q=0.6 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 Log from Fiddler 2 of the request: This session is not yet complete. Press F5 to refresh when session is complete for updated statistics. Request Count: 1 Bytes Sent: 567 (headers:567; body:0) Bytes Received: 0 (headers:0; body:0) ACTUAL PERFORMANCE -------------- ClientConnected: 17:02:33.720 ClientBeginRequest: 17:02:39.118 GotRequestHeaders: 17:02:39.118 ClientDoneRequest: 17:02:39.118 Determine Gateway: 0ms DNS Lookup: 0ms TCP/IP Connect: 46ms HTTPS Handshake: 0ms ServerConnected: 17:02:39.165 FiddlerBeginRequest: 17:02:39.165 ServerGotRequest: 17:02:39.165 ServerBeginResponse: 00:00:00.000 GotResponseHeaders: 00:00:00.000 ServerDoneResponse: 00:00:00.000 ClientBeginResponse: 00:00:00.000 ClientDoneResponse: 00:00:00.000 RESPONSE BYTES (by Content-Type) -------------- ~headers~: 0 Log of a successful request from a working PC (done this morning, excuse the timestamps being different from above): Request Count: 1 Bytes Sent: 493 (headers:493; body:0) Bytes Received: 20,413 (headers:525; body:19,888) ACTUAL PERFORMANCE -------------- ClientConnected: 08:22:47.766 ClientBeginRequest: 08:22:47.766 GotRequestHeaders: 08:22:47.766 ClientDoneRequest: 08:22:47.766 Determine Gateway: 0ms DNS Lookup: 26ms TCP/IP Connect: 30ms HTTPS Handshake: 0ms ServerConnected: 08:22:47.828 FiddlerBeginRequest: 08:22:47.828 ServerGotRequest: 08:22:47.828 ServerBeginResponse: 08:22:48.905 GotResponseHeaders: 08:22:48.905 ServerDoneResponse: 08:22:48.905 ClientBeginResponse: 08:22:48.905 ClientDoneResponse: 08:22:48.905 Overall Elapsed: 00:00:01.1388020 RESPONSE BYTES (by Content-Type) -------------- text/html: 19,888 ~headers~: 525 So my question has evolved into: What is the difference between the 2 requests and how do I determine why 1 PC is not getting a reply to it's GET request?

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• dns queries not using nscd for caching

  - by xenoterracide

  I'm trying to use nscd (Nameservices Cache Daemon) to cache dns locally so I can stop using bind to do it. I've gotten it started and ntpd seems to attempt to use it. But everything else for hosts seems to ignore it. e.g if I do dig apache.org 3 times none of them will hit the cache. I'm viewing the cache stats using nscd -g to determine whether it's been used. I've also turned the debug log level up to see if I can see it hitting and the queries don't even hit nscd. nsswitch.conf # Begin /etc/nsswitch.conf passwd: files group: files shadow: files publickey: files hosts: cache files dns networks: files protocols: files services: files ethers: files rpc: files netgroup: files # End /etc/nsswitch.confenter code here nscd.conf # # /etc/nscd.conf # # An example Name Service Cache config file. This file is needed by nscd. # # Legal entries are: # # logfile <file> # debug-level <level> # threads <initial #threads to use> # max-threads <maximum #threads to use> # server-user <user to run server as instead of root> # server-user is ignored if nscd is started with -S parameters # stat-user <user who is allowed to request statistics> # reload-count unlimited|<number> # paranoia <yes|no> # restart-interval <time in seconds> # # enable-cache <service> <yes|no> # positive-time-to-live <service> <time in seconds> # negative-time-to-live <service> <time in seconds> # suggested-size <service> <prime number> # check-files <service> <yes|no> # persistent <service> <yes|no> # shared <service> <yes|no> # max-db-size <service> <number bytes> # auto-propagate <service> <yes|no> # # Currently supported cache names (services): passwd, group, hosts, services # logfile /var/log/nscd.log threads 4 max-threads 32 server-user nobody # stat-user somebody debug-level 9 # reload-count 5 paranoia no # restart-interval 3600 enable-cache passwd yes positive-time-to-live passwd 600 negative-time-to-live passwd 20 suggested-size passwd 211 check-files passwd yes persistent passwd yes shared passwd yes max-db-size passwd 33554432 auto-propagate passwd yes enable-cache group yes positive-time-to-live group 3600 negative-time-to-live group 60 suggested-size group 211 check-files group yes persistent group yes shared group yes max-db-size group 33554432 auto-propagate group yes enable-cache hosts yes positive-time-to-live hosts 3600 negative-time-to-live hosts 20 suggested-size hosts 211 check-files hosts yes persistent hosts yes shared hosts yes max-db-size hosts 33554432 enable-cache services yes positive-time-to-live services 28800 negative-time-to-live services 20 suggested-size services 211 check-files services yes persistent services yes shared services yes max-db-size services 33554432 resolv.conf # Generated by dhcpcd from eth0 nameserver 127.0.0.1 domain westell.com nameserver 192.168.1.1 nameserver 208.67.222.222 nameserver 208.67.220.220 as kind of a side note I'm using archlinux.

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• Installing .NET Framework 4 Client Profile breaks Windows Update

  - by Richard

  I have a Samsung NC-10 netbook with a fresh install of Windows 7 Home Premium 32-bit (it only had 2GB). If Microsoft .NET Framework 4 Client Profile is installed on it, Windows Update will always return error code 8024402F ("Windows Update encountered an unknown error"). As soon as I uninstall it, Windows Update works just fine again. Out of the four computers in this house, only this netbook has the problem. My question is: How can I get the .NET Framework 4 Client Profile installed on my netbook and continue to have a functioning Windows Update? ----- More information ----- The hard-drive recently died on my netbook so I replaced it with a nice new SSD and did a fresh installation of Windows 7 Home Premium (SP1) - along with all the updates. At some point I found that, when I ran Windows Update, I was greeted with error code 8024402F ("Windows Update encountered an unknown error"). Looking in C:\Windows\WindowsUpdate.log, I saw the following issue: WARNING: ECP: Failed to validate cab file digest downloaded from http://download.windowsupdate.com/msdownload/update/software/dflt/2012/02/4913552_4a5c9563d1f58c77f30d0d5c9999e4b8bff3ab21.cab with error 0x80091007 WARNING: ECP: This roundtrip contained some optimized updates which failed. New Update count = 0, Old Count = 3 FATAL: ProcessCoreMetadata did not return any update to be committed WARNING: Sync of Updates: 0x8024402f WARNING: SyncServerUpdatesInternal failed: 0x8024402f When I downloaded the CAB from the URL listed and opened it, it contained a file called 4913552.txt. A search on Google suggested that it's related to Microsoft .NET Framework 4 Client Profile. Other people had reported problems with it breaking Windows Update, but they were running Windows XP. I tried the steps outlined on the Microsoft site for this error code, but it reported that there was nothing wrong. I also found this superuser question, I tried all the answers listed but none of them made any difference. My router doesn't block ActiveX, changing my internet settings in IE made no difference, assuming it was a corrupted update repository didn't do anything (except wipe my update history), my date and time was correct, switching to Google's DNS didn't work and neither did disabling IPv6. Figuring that this update was corrupted, I repaired it and nothing changed. In desperation I un-installed it and Windows Update started working again! Brilliant! I then downloaded the full version from the Microsoft website, installed it and, thankfully, Windows Update continued to work just fine. A week later I turn on my netbook and Windows Update is broken again with exactly the same error message and log entries as before. Repairing .NET Framework 4 Client Profile did nothing, removing it entirely solved the problem again. Thinking this might be some odd Windows installation issue, I formatted the hard-drive and re-installed Windows. Same problem as before - as soon as .NET Framework 4 Client Profile ended up on the netbook, Windows Update stopped working and reported error 8024402F. As soon as it was un-installed, everything worked just fine again. There are three other machines in this house and all of them have working Windows Update and this Client Profile. Does anyone know why it causes this netbook to break and, more importantly, how I can fix it?

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• e2fsck / resize2fs problems

  - by BlakBat

  I've got 6 drives (each 1.5T, all same model and firmware revision) that are part of a RAID5 array. The RAID5 makes a LVM volume group and a logical group. The latter contains only one ext3 partition. I've recently ran: e2fsck -f /dev/vg03/lv01 && resize2fs -M /dev/vg03/lv01 which exited without an error. Now when I try to mount /dev/vg03/lv01 I get: EXT3-fs error (device dm-0): ext3_check_descriptors: Block bitmap for group 30533 not in group (block 1000532368)! EXT3-fs: group descriptors corrupted! How do I get out of this predicament? This is all the info I can currently give you: fdisk -l /dev/sd[cdefgh] shows (correctly) that they are "Linux raid autodetect" but fdisk now shows: fdisk -l /dev/md0 Disk /dev/md0: 7501.5 GB, 7501495664640 bytes ... Disk identifier: 0x00000000 Disk /dev/md0 doesn't contain a valid partition table (instead of a LVM type partition) fdisk -l /dev/vg03/lv01 Disk /dev/vg03/lv01: 7501.5 GB, 7501491732480 bytes ... Disk identifier: 0x00000000 Disk /dev/vg03/lv01 doesn't contain a valid partition table (instead of a ext3 type partition) I've tried: e2fsck -fy /dev/vg03/lv01 e2fsck 1.41.12 (17-May-2010) e2fsck: Group descriptors look bad... trying backup blocks... Block bitmap for group 30533 is not in group. (block 1000532368) Relocate? yes Inode bitmap for group 30533 is not in group. (block 1000532369) Relocate? yes Pass 1: Checking inodes, blocks, and sizes Relocating group 30533's block bitmap to 1000524246... Error allocating 1 contiguous block(s) in block group 30533 for inode bitmap: Could not allocate block in ext2 filesystem e2fsck: aborted Extra information I can give you: cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active (auto-read-only) raid5 sdg1[0] sdh1[5] sdf1[4] sde1[3] sdc1[2] sdd1[1] 7325679360 blocks level 5, 128k chunk, algorithm 2 [6/6] [UUUUUU] bitmap: 1/175 pages [4KB], 4096KB chunk unused devices: Lastly, all smartctl tests (short and extendend) showed no errors on any of the disks. Should I try to resize2fs to grow /dev/vg03/lv01 and redo a e2fsck ? Should I cfdisk /dev/md0 and /dev/vg03/lv01 back to their real types? Thanks in advance for all and any help. 2011-09-20 UPDATE I issued the following commands and was able to remount the partition, but by viewing the size (df) of before and after, it seems that 1Tb of data have gone missing. By checking the MD5SUMS (from an old backup) of some files with the "same" files from the remounted partition, some errors have been detected. Commands issued to remount the partition were: dumpe2fs /dev/vg03/lv01 Block count: 1000491435<br /> Block size: 4096<br /> tune2fs -O ^has_journal /dev/vg03/lv01 resize2fs -p /dev/vg03/lv01 dumpe2fs /dev/vg03/lv01 Block count: 1831418880<br /> Block size: 4096<br /> mount -o ro,noatime /dev/vg03/lv01 /mnt/raid OK... but files have been damaged / gone missing.

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• Linux software RAID6: rebuild slow

  - by Ole Tange

  I am trying to find the bottleneck in the rebuilding of a software raid6. ## Pause rebuilding when measuring raw I/O performance # echo 1 > /proc/sys/dev/raid/speed_limit_min # echo 1 > /proc/sys/dev/raid/speed_limit_max ## Drop caches so that does not interfere with measuring # sync ; echo 3 | tee /proc/sys/vm/drop_caches >/dev/null # time parallel -j0 "dd if=/dev/{} bs=256k count=4000 | cat >/dev/null" ::: sdbd sdbc sdbf sdbm sdbl sdbk sdbe sdbj sdbh sdbg 4000+0 records in 4000+0 records out 1048576000 bytes (1.0 GB) copied, 7.30336 s, 144 MB/s [... similar for each disk ...] # time parallel -j0 "dd if=/dev/{} skip=15000000 bs=256k count=4000 | cat >/dev/null" ::: sdbd sdbc sdbf sdbm sdbl sdbk sdbe sdbj sdbh sdbg 4000+0 records in 4000+0 records out 1048576000 bytes (1.0 GB) copied, 12.7991 s, 81.9 MB/s [... similar for each disk ...] So we can read sequentially at 140 MB/s in the outer tracks and 82 MB/s in the inner tracks on all the drives simultaneously. Sequential write performance is similar. This would lead me to expect a rebuild speed of 82 MB/s or more. # echo 800000 > /proc/sys/dev/raid/speed_limit_min # echo 800000 > /proc/sys/dev/raid/speed_limit_max # cat /proc/mdstat md2 : active raid6 sdbd[10](S) sdbc[9] sdbf[0] sdbm[8] sdbl[7] sdbk[6] sdbe[11] sdbj[4] sdbi[3](F) sdbh[2] sdbg[1] 27349121408 blocks super 1.2 level 6, 128k chunk, algorithm 2 [9/8] [UUU_UUUUU] [=========>...........] recovery = 47.3% (1849905884/3907017344) finish=855.9min speed=40054K/sec But we only get 40 MB/s. And often this drops to 30 MB/s. # iostat -dkx 1 sdbc 0.00 8023.00 0.00 329.00 0.00 33408.00 203.09 0.70 2.12 1.06 34.80 sdbd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 sdbe 13.00 0.00 8334.00 0.00 33388.00 0.00 8.01 0.65 0.08 0.06 47.20 sdbf 0.00 0.00 8348.00 0.00 33388.00 0.00 8.00 0.58 0.07 0.06 48.00 sdbg 16.00 0.00 8331.00 0.00 33388.00 0.00 8.02 0.71 0.09 0.06 48.80 sdbh 961.00 0.00 8314.00 0.00 37100.00 0.00 8.92 0.93 0.11 0.07 54.80 sdbj 70.00 0.00 8276.00 0.00 33384.00 0.00 8.07 0.78 0.10 0.06 48.40 sdbk 124.00 0.00 8221.00 0.00 33380.00 0.00 8.12 0.88 0.11 0.06 47.20 sdbl 83.00 0.00 8262.00 0.00 33380.00 0.00 8.08 0.96 0.12 0.06 47.60 sdbm 0.00 0.00 8344.00 0.00 33376.00 0.00 8.00 0.56 0.07 0.06 47.60 iostat says the disks are not 100% busy (but only 40-50%). This fits with the hypothesis that the max is around 80 MB/s. Since this is software raid the limiting factor could be CPU. top says: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 38520 root 20 0 0 0 0 R 64 0.0 2947:50 md2_raid6 6117 root 20 0 0 0 0 D 53 0.0 473:25.96 md2_resync So md2_raid6 and md2_resync are clearly busy taking up 64% and 53% of a CPU respectively, but not near 100%. The chunk size (128k) of the RAID was chosen after measuring which chunksize gave the least CPU penalty. If this speed is normal: What is the limiting factor? Can I measure that? If this speed is not normal: How can I find the limiting factor? Can I change that?

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• Determining the required depth and specifications for a server cabinet

  - by Bingu Bingme

  I'm trying to understand the considerations ("why") that go into determining the specifications ("what") for a rackmount server cabinet, in order to determine what sort of rack I should purchase for my home use. Since this is for home use, I won't be following certain best practices (eg. hot/cold aisle, not even air conditioning) and may be willing to sacrifice in various areas in order to reduce cost and footprint - but please advise if there are safety concerns or other considerations to note. The most basic specs for a server cabinet are the dimensions (external width x external depth x usable height). Width: commonly 600mm or 800mm (if the use case requires extra clearance around the sides, such as if there is lots of cabling). In my case and most common cases, I'm going to stick with 600mm. Height: Select a sufficiently tall rack to fit my equipment. But how much may I stuff into it? Eg, if there is a 15U rack, can I really populate it with 15U of servers, or should I leave 1U at top and bottom for air circulation? Depth: Racks commonly have external depth of 600mm (network equipment), 800mm, 1000mm, or even longer. I'm trying to see how to fit into the 800mm depth. With reference to http://www.server-racks.com/rack-mount-depth.html, I'm hoping to have the front and rear posts mounted ~ 28.5" (72cm) apart, which would leave only 8cm for front space and rear space. How much rear space (from rear posts to back of rack) do I really need? I won't use cable management arms, so can I mount a 72cm depth server since the power, KVM, network cables won't take up much depth? My most important equipment are all < 60cm depth (4U chassis) and should comfortably fit within the 800mm cabinet. The rest of the equipment are very old 1U servers that range from 65-72cm depth. I might still want to make further use of them, or I might discard them since they are so old. Even if the 72cm servers cannot be powered on in an 800mm rack, I should be able to use them as 1U shelves. But, what server depth can I expect to be able to operate? Or am I forced to upgrade to 1000mm depth racks in order to use any servers deeper than 60cm? With reference to best practices for HP racks, some other specs and installation considerations: There aren't any minimum recommendations for clearance on the sides of the rack. It is recommended to leave 48" front clearance. The 48" front clearance is based on 32" chassis depth, 13" to extend the rack rails and mate the inner/outer rails, and 3" for movement. If I don't use such rails (eg, use shelves instead), it should be sufficient to leave front clearance of chassis depth + 3". It is recommended to leave 30" rear clearance "to provide space for servicing the rack". I'm planning to back the rack into a corner of the room, and wheel it slightly out when I need to access the rear. If the wheeling plan is ok, I still need to know how much rear clearance is required for air circulation and ventilation purposes. Castor wheels and stabilising feet. Since I'm backing the rack into a corner of the room, I'll only be able to set the stabilising feet on the front corners. Thoughts on safety? The rack that I'm considering has front glass doors with side ventilation slits and fully perforated rear doors. I'm hoping this will be a good balance between temperature and noise (only ventilation slits facing out the front, while the rear is facing the walls). Or is the sound of high-rpm fans going to escape through the front slits anyway and destroy my sanity?

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• What's the difference between find and findstr commands in Windows?

  - by Prashant Bhate

  In Windows, what are the differences between find and findstr commands? Both seems to search text in files: find c:\>find /? Searches for a text string in a file or files. FIND [/V] [/C] [/N] [/I] [/OFF[LINE]] "string" [[drive:][path]filename[ ...]] /V Displays all lines NOT containing the specified string. /C Displays only the count of lines containing the string. /N Displays line numbers with the displayed lines. /I Ignores the case of characters when searching for the string. /OFF[LINE] Do not skip files with offline attribute set. "string" Specifies the text string to find. [drive:][path]filename Specifies a file or files to search. If a path is not specified, FIND searches the text typed at the prompt or piped from another command. findstr c:\>findstr /? Searches for strings in files. FINDSTR [/B] [/E] [/L] [/R] [/S] [/I] [/X] [/V] [/N] [/M] [/O] [/P] [/F:file] [/C:string] [/G:file] [/D:dir list] [/A:color attributes] [/OFF[LINE]] strings [[drive:][path]filename[ ...]] /B Matches pattern if at the beginning of a line. /E Matches pattern if at the end of a line. /L Uses search strings literally. /R Uses search strings as regular expressions. /S Searches for matching files in the current directory and all subdirectories. /I Specifies that the search is not to be case-sensitive. /X Prints lines that match exactly. /V Prints only lines that do not contain a match. /N Prints the line number before each line that matches. /M Prints only the filename if a file contains a match. /O Prints character offset before each matching line. /P Skip files with non-printable characters. /OFF[LINE] Do not skip files with offline attribute set. /A:attr Specifies color attribute with two hex digits. See "color /?" /F:file Reads file list from the specified file(/ stands for console). /C:string Uses specified string as a literal search string. /G:file Gets search strings from the specified file(/ stands for console). /D:dir Search a semicolon delimited list of directories strings Text to be searched for. [drive:][path]filename Specifies a file or files to search. Use spaces to separate multiple search strings unless the argument is prefixed with /C. For example, 'FINDSTR "hello there" x.y' searches for "hello" or "there" in file x.y. 'FINDSTR /C:"hello there" x.y' searches for "hello there" in file x.y. Regular expression quick reference: . Wildcard: any character * Repeat: zero or more occurances of previous character or class ^ Line position: beginning of line $ Line position: end of line [class] Character class: any one character in set [^class] Inverse class: any one character not in set [x-y] Range: any characters within the specified range \x Escape: literal use of metacharacter x \<xyz Word position: beginning of word xyz\> Word position: end of word For full information on FINDSTR regular expressions refer to the online Command Reference.

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• Multi-tenant ASP.NET MVC – Introduction

  - by zowens

  I’ve read a few different blogs that talk about multi-tenancy and how to resolve some of the issues surrounding multi-tenancy. What I’ve come to realize is that these implementations overcomplicate the issues and give only a muddy implementation! I’ve seen some really illogical code out there. I have recently been building a multi-tenancy framework for internal use at eagleenvision.net. Through this process, I’ve realized a few different techniques to make building multi-tenant applications actually quite easy. I will be posting a few different entries over the issue and my personal implementation. In this first post, I will discuss what multi-tenancy means and how my implementation will be structured.   So what’s the problem? Here’s the deal. Multi-tenancy is basically a technique of code-reuse of web application code. A multi-tenant application is an application that runs a single instance for multiple clients. Here the “client” is different URL bindings on IIS using ASP.NET MVC. The problem with different instances of the, essentially, same application is that you have to spin up different instances of ASP.NET. As the number of running instances of ASP.NET grows, so does the memory footprint of IIS. Stack Exchange shifted its architecture to multi-tenancy March. As the blog post explains, multi-tenancy saves cost in terms of memory utilization and physical disc storage. If you use the same code base for many applications, multi-tenancy just makes sense. You’ll reduce the amount of work it takes to synchronize the site implementations and you’ll thank your lucky stars later for choosing to use one application for multiple sites. Multi-tenancy allows the freedom of extensibility while relying on some pre-built code.   You’d think this would be simple. I have actually seen a real lack of reference material on the subject in terms of ASP.NET MVC. This is somewhat surprising given the number of users of ASP.NET MVC. However, I will certainly fill the void ;). Implementing a multi-tenant application takes a little thinking. It’s not straight-forward because the possibilities of implementation are endless. I have yet to see a great implementation of a multi-tenant MVC application. The only one that comes close to what I have in mind is Rob Ashton’s implementation (all the entries are listed on this page). There’s some really nasty code in there… something I’d really like to avoid. He has also written a library (MvcEx) that attempts to aid multi-tenant development. This code is even worse, in my honest opinion. Once I start seeing Reflection.Emit, I have to assume the worst :) In all seriousness, if his implementation makes sense to you, use it! It’s a fine implementation that should be given a look. At least look at the code. I will reference MvcEx going forward as a comparison to my implementation. I will explain why my approach differs from MvcEx and how it is better or worse (hopefully better).   Core Goals of my Multi-Tenant Implementation The first, and foremost, goal is to use Inversion of Control containers to my advantage. As you will see throughout this series, I pass around containers quite frequently and rely on their use heavily. I will be using StructureMap in my implementation. However, you could probably use your favorite IoC tool instead. <RANT> However, please don’t be stupid and abstract your IoC tool. Each IoC is powerful and by abstracting the capabilities, you’re doing yourself a real disservice. Who in the world swaps out IoC tools…? No one!</RANT> (It had to be said.) I will outline some of the goodness of StructureMap as we go along. This is really an invaluable tool in my tool belt and simple to use in my multi-tenant implementation. The second core goal is to represent a tenant as easily as possible. Just as a dependency container will be a first-class citizen, so will a tenant. This allows us to easily extend and use tenants. This will also allow different ways of “plugging in” tenants into your application. In my implementation, there will be a single dependency container for a single tenant. This will enable isolation of the dependencies of the tenant. The third goal is to use composition as a means to delegate “core” functions out to the tenant. More on this later.   Features In MvcExt, “Modules” are a code element of the infrastructure. I have simplified this concept and have named this “Features”. A feature is a simple element of an application. Controllers can be specified to have a feature and actions can have “sub features”. Each tenant can select features it needs and the other features will be hidden to the tenant’s users. My implementation doesn’t require something to be a feature. A controller can be common to all tenants. For example, (as you will see) I have a “Content” controller that will return the CSS, Javascript and Images for a tenant. This is common logic to all tenants and shouldn’t be hidden or considered a “feature”; Content is a core component.   Up next My next post will be all about the code. I will reveal some of the foundation to the way I do multi-tenancy. I will have posts dedicated to Foundation, Controllers, Views, Caching, Content and how to setup the tenants. Each post will be in-depth about the issues and implementation details, while adhering to my core goals outlined in this post. As always, comment with questions of DM me on twitter or send me an email.

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• Using TypeScript in ASP.NET MVC Projects

  - by shiju

  In the previous blog post Microsoft TypeScript : A Typed Superset of JavaScript, I have given a brief introduction on TypeScript. In this post, I will demonstrate how to use TypeScript with ASP.NET MVC projects and how we can compile TypeScript within the ASP.NET MVC projects. Using TypeScript with ASP.NET MVC 3 Projects The Visual Studio plug-in for TypeScript provides an ASP.NET MVC 3 project template for TypeScript that lets you to compile TypeScript from the Visual Studio. The following screen shot shows the TypeScript template for ASP.NET MVC 3 project The “TypeScript Internet Application” template is just a ASP.NET MVC 3 internet application project template which will allows to compile TypeScript programs to JavaScript when you are building your ASP.NET MVC projects. This project template will have the following section in the .csproject file <None Include="Scripts\jquery.d.ts" /> <TypeScriptCompile Include="Scripts\site.ts" /> <Content Include="Scripts\site.js"> <DependentUpon>site.ts</DependentUpon> </Content> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } <Target Name="BeforeBuild"> <Exec Command="&amp;quot;$(PROGRAMFILES)\ Microsoft SDKs\TypeScript\0.8.0.0\tsc&amp;quot; @(TypeScriptCompile ->'&quot;%(fullpath)&quot;', ' ')" /> </Target> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The “BeforeBuild” target will allows you to compile TypeScript programs when you are building your ASP.NET MVC projects. The TypeScript project template will provide a typing reference file for the jQuery library named “jquery.d.ts”. The following default app.ts file referenced to jquery.d.ts 1: ///<reference path='jquery.d.ts' /> 2:   3: $(document).ready(function () { 4:   5: $(".btn-slide").click(function () { 6: $("#main").slideToggle("slow"); 7: $(this).toggleClass("active"); 8: }); 9:   10: }); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Using TypeScript with ASP.NET MVC 4 Projects The current preview version of TypeScript is not providing a project template for ASP.NET MVC 4 projects. But you can use TypeScript with ASP.NET MVC 4 projects by editing the project’s .csproject file. You can take the necessary settings from ASP.NET MVC 3 project file. I have just added the following section in the end of the .csproj file of a ASP.NET MVC 4 project, which will allows to compile all TypeScript when building ASP.NET MVC 4 project. <ItemGroup> <TypeScriptCompile Include="$(ProjectDir)\**\*.ts" /> </ItemGroup> <Target Name="BeforeBuild"> <Exec Command="&amp;quot;$(PROGRAMFILES)\ Microsoft SDKs\TypeScript\0.8.0.0\tsc&amp;quot; @(TypeScriptCompile ->'&quot;%(fullpath)&quot;', ' ')" /> </Target> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }

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• Consume WCF Service InProcess using Agatha and WCF

  - by REA_ANDREW

  I have been looking into this lately for a specific reason.  Some integration tests I want to write I want to control the types of instances which are used inside the service layer but I want that control from the test class instance.  One of the problems with just referencing the service is that a lot of the time this will by default be done inside a different process.  I am using StructureMap as my DI of choice and one of the tools which I am using inline with RhinoMocks is StructureMap.AutoMocking.  With StructureMap the main entry point is the ObjectFactory.  This will be process specific so if I decide that the I want a certain instance of a type to be used inside the ServiceLayer I cannot configure the ObjectFactory from my test class as that will only apply to the process which it belongs to. This is were I started thinking about two things: Running a WCF in process Being able to share mocked instances across processes A colleague in work pointed me to a project which is for the latter but I thought that it would be a better solution if I could run the WCF Service in process.  One of the projects which I use when I think about WCF Services is AGATHA, and the one which I have to used to try and get my head around doing this. Another asset I have is a book called Programming WCF Services by Juval Lowy and if you have not heard of it or read it I would definately recommend it.  One of the many topics that is inside this book is the type of configuration you need to communicate with a service in the same process, and it turns out to be quite simple from a config point of view. <system.serviceModel> <services> <service name="Agatha.ServiceLayer.WCF.WcfRequestProcessor"> <endpoint address ="net.pipe://localhost/MyPipe" binding="netNamedPipeBinding" contract="Agatha.Common.WCF.IWcfRequestProcessor"/> </service> </services> <client> <endpoint name="MyEndpoint" address="net.pipe://localhost/MyPipe" binding="netNamedPipeBinding" contract="Agatha.Common.WCF.IWcfRequestProcessor"/> </client> </system.serviceModel>   You can see here that I am referencing the Agatha object and contract here, but also that my binding and the address is something called Named Pipes.  THis is sort of the “Magic” which makes it happen in the same process. Next I need to open the service prior to calling the methods on a proxy which I also need.  My initial attempt at the proxy did not use any Agatha specific coding and one of the pains I found was that you obviously need to give your proxy the known types which the serializer can be aware of.  So we need to add to the known types of the proxy programmatically.  I came across the following blog post which showed me how easy it was http://bloggingabout.net/blogs/vagif/archive/2009/05/18/how-to-programmatically-define-known-types-in-wcf.aspx. First Pass So with this in mind, and inside a console app this was my first pass at consuming a service in process.  First here is the proxy which I made making use of the Agatha IWcfRequestProcessor contract. public class InProcProxy : ClientBase<Agatha.Common.WCF.IWcfRequestProcessor>, Agatha.Common.WCF.IWcfRequestProcessor { public InProcProxy() { } public InProcProxy(string configurationName) : base(configurationName) { } public Agatha.Common.Response[] Process(params Agatha.Common.Request[] requests) { return Channel.Process(requests); } public void ProcessOneWayRequests(params Agatha.Common.OneWayRequest[] requests) { Channel.ProcessOneWayRequests(requests); } } So with the proxy in place I could then use this after opening the service so here is the code which I use inside the console app make the request. static void Main(string[] args) { ComponentRegistration.Register(); ServiceHost serviceHost = new ServiceHost(typeof(Agatha.ServiceLayer.WCF.WcfRequestProcessor)); serviceHost.Open(); Console.WriteLine("Service is running...."); using (var proxy = new InProcProxy()) { foreach (var operation in proxy.Endpoint.Contract.Operations) { foreach (var t in KnownTypeProvider.GetKnownTypes(null)) { operation.KnownTypes.Add(t); } } var request = new GetProductsRequest(); var responses = proxy.Process(new[] { request }); var response = (GetProductsResponse)responses[0]; Console.WriteLine("{0} Products have been retrieved", response.Products.Count); } serviceHost.Close(); Console.WriteLine("Finished"); Console.ReadLine(); } So what I used here is the KnownTypeProvider of Agatha to easily get all the types I need for the service/proxy and add them to the proxy.  My Request handler for this was just a test one which always returned 2 products. public class GetProductsHandler : RequestHandler<GetProductsRequest,GetProductsResponse> { public override Agatha.Common.Response Handle(GetProductsRequest request) { return new GetProductsResponse { Products = new List<ProductDto> { new ProductDto{}, new ProductDto{} } }; } } Second Pass Now after I did this I started reading up some more on some resources including more by Davy Brion and others on Agatha.  Now it turns out that the work I did above to create a derived class of the ClientBase implementing Agatha.Common.WCF.IWcfRequestProcessor was not necessary due to a nice class which is present inside the Agatha code base, RequestProcessorProxy which takes care of this for you! :-) So disregarding that class I made for the proxy and changing my code to use it I am now left with the following: static void Main(string[] args) { ComponentRegistration.Register(); ServiceHost serviceHost = new ServiceHost(typeof(Agatha.ServiceLayer.WCF.WcfRequestProcessor)); serviceHost.Open(); Console.WriteLine("Service is running...."); using (var proxy = new RequestProcessorProxy()) { var request = new GetProductsRequest(); var responses = proxy.Process(new[] { request }); var response = (GetProductsResponse)responses[0]; Console.WriteLine("{0} Products have been retrieved", response.Products.Count); } serviceHost.Close(); Console.WriteLine("Finished"); Console.ReadLine(); }   Cheers for now, Andy References Agatha WCF InProcess Without WCF StructureMap.AutoMocking Cross Process Mocking Agatha Programming WCF Services by Juval Lowy

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• Silverlight 4 Tools for VS 2010 and WCF RIA Services Released

  - by ScottGu

  The final release of the Silverlight 4 Tools for Visual Studio 2010 and WCF RIA Services is now available for download.  Download and Install If you already have Visual Studio 2010 installed (or the free Visual Web Developer 2010 Express), then you can install both the Silverlight 4 Tooling Support as well as WCF RIA Services support by downloading and running this setup package (note: please make sure to uninstall the preview release of the Silverlight 4 Tools for VS 2010 if you have previously installed that).  The Silverlight 4 Tools for VS 2010 package extends the Silverlight support built into Visual Studio 2010 and enables support for Silverlight 4 applications as well.  It also installs WCF RIA Services application templates and libraries: Today’s release includes the English edition of the Silverlight 4 Tooling – localized versions will be available next month for other Visual Studio languages as well. Silverlight Tooling Support Visual Studio 2010 includes rich tooling support for building Silverlight and WPF applications. It includes a WYSIWYG designer surface that enables you to easily use controls to construct UI – including the ability to take advantage of layout containers, and apply styles and resources: The VS 2010 designer enables you to leverage the rich data binding support within Silverlight and WPF, and easily wire-up bindings on controls.  The Data Sources window within Silverlight projects can be used to reference POCO objects (plain old CLR objects), WCF Services, WCF RIA Services client proxies or SharePoint Lists.  For example, let’s assume we add a “Person” class like below to our project: We could then add it to the Data Source window which will cause it to show up like below in the IDE: We can optionally customize the default UI control types that are associated for each property on the object.  For example, below we’ll default the BirthDate property to be represented by a “DatePicker” control: And then when we drag/drop the Person type from the Data Sources onto the design-surface it will automatically create UI controls that are bound to the properties of our Person class: VS 2010 allows you to optionally customize each UI binding further by selecting a control, and then right-click on any of its properties within the property-grid and pull up the “Apply Bindings” dialog: This will bring up a floating data-binding dialog that enables you to easily configure things like the binding path on the data source object, specify a format convertor, specify string-format settings, specify how validation errors should be handled, etc: In addition to providing WYSIWYG designer support for WPF and Silverlight applications, VS 2010 also provides rich XAML intellisense and code editing support – enabling a rich source editing environment. Silverlight 4 Tool Enhancements Today’s Silverlight 4 Tooling Release for VS 2010 includes a bunch of nice new features.  These include: Support for Silverlight Out of Browser Applications and Elevated Trust Applications You can open up a Silverlight application’s project properties window and click the “Enable Running Application Out of Browser” checkbox to enable you to install an offline, out of browser, version of your Silverlight 4 application.  You can then customize a number of “out of browser” settings of your application within Visual Studio: Notice above how you can now indicate that you want to run with elevated trust, with hardware graphics acceleration, as well as customize things like the Window style of the application (allowing you to build a nice polished window style for consumer applications). Support for Implicit Styles and “Go to Value Definition” Support: Silverlight 4 now allows you to define “implicit styles” for your applications.  This allows you to style controls by type (for example: have a default look for all buttons) and avoid you having to explicitly reference styles from each control.  In addition to honoring implicit styles on the designer-surface, VS 2010 also now allows you to right click on any control (or on one of it properties) and choose the “Go to Value Definition…” context menu to jump to the XAML where the style is defined, and from there you can easily navigate onward to any referenced resources.  This makes it much easier to figure out questions like “why is my button red?”: Style Intellisense VS 2010 enables you to easily modify styles you already have in XAML, and now you get intellisense for properties and their values within a style based on the TargetType of the specified control.  For example, below we have a style being set for controls of type “Button” (this is indicated by the “TargetType” property).  Notice how intellisense now automatically shows us properties for the Button control (even within the <Setter> element): Great Video - Watch the Silverlight Designer Features in Action You can see all of the above Silverlight 4 Tools for Visual Studio 2010 features (and some more cool ones I haven’t mentioned) demonstrated in action within this 20 minute Silverlight.TV video on Channel 9: WCF RIA Services Today we also shipped the V1 release of WCF RIA Services.  It is included and automatically installed as part of the Silverlight 4 Tools for Visual Studio 2010 setup. WCF RIA Services makes it much easier to build business applications with Silverlight.  It simplifies the traditional n-tier application pattern by bringing together the ASP.NET and Silverlight platforms using the power of WCF for communication.  WCF RIA Services provides a pattern to write application logic that runs on the mid-tier and controls access to data for queries, changes and custom operations. It also provides end-to-end support for common tasks such as data validation, authentication and authorization based on roles by integrating with Silverlight components on the client and ASP.NET on the mid-tier. Put simply – it makes it much easier to query data stored on a server from a client machine, optionally manipulate/modify the data on the client, and then save it back to the server.  It supports a validation architecture that helps ensure that your data is kept secure and business rules are applied consistently on both the client and middle-tiers. WCF RIA Services uses WCF for communication between the client and the server  It supports both an optimized .NET to .NET binary serialization format, as well as a set of open extensions to the ATOM format known as ODATA and an optional JavaScript Object Notation (JSON) format that can be used by any client. You can hear Nikhil and Dinesh talk a little about WCF RIA Services in this 13 minutes Channel 9 video. Putting it all Together – the Silverlight 4 Training Kit Check out the Silverlight 4 Training Kit to learn more about how to build business applications with Silverlight 4, Visual Studio 2010 and WCF RIA Services. The training kit includes 8 modules, 25 videos, and several hands-on labs that explain Silverlight 4 and WCF RIA Services concepts and walks you through building an end-to-end application with them.    The training kit is available for free and is a great way to get started. Summary I’m really excited about today’s release – as they really complete the Silverlight development story and deliver a great end to end runtime + tooling story for building applications.  All of the above features are available for use both in VS 2010 as well as the free Visual Web Developer 2010 Express Edition – making it really easy to get started building great solutions. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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• Dependency Injection in ASP.NET MVC NerdDinner App using Ninject

  - by shiju

  In this post, I am applying Dependency Injection to the NerdDinner application using Ninject. The controllers of NerdDinner application have Dependency Injection enabled constructors. So we can apply Dependency Injection through constructor without change any existing code. A Dependency Injection framework injects the dependencies into a class when the dependencies are needed. Dependency Injection enables looser coupling between classes and their dependencies and provides better testability of an application and it removes the need for clients to know about their dependencies and how to create them. If you are not familiar with Dependency Injection and Inversion of Control (IoC), read Martin Fowler’s article Inversion of Control Containers and the Dependency Injection pattern. The Open Source Project NerDinner is a great resource for learning ASP.NET MVC.  A free eBook provides an end-to-end walkthrough of building NerdDinner.com application. The free eBook and the Open Source Nerddinner application are extremely useful if anyone is trying to lean ASP.NET MVC. The first release of  Nerddinner was as a sample for the first chapter of Professional ASP.NET MVC 1.0. Currently the application is updating to ASP.NET MVC 2 and you can get the latest source from the source code tab of Nerddinner at http://nerddinner.codeplex.com/SourceControl/list/changesets. I have taken the latest ASP.NET MVC 2 source code of the application and applied  Dependency Injection using Ninject and Ninject extension Ninject.Web.Mvc.Ninject &  Ninject.Web.MvcNinject is available at http://github.com/enkari/ninject and Ninject.Web.Mvc is available at http://github.com/enkari/ninject.web.mvcNinject is a lightweight and a great dependency injection framework for .NET.  Ninject is a great choice of dependency injection framework when building ASP.NET MVC applications. Ninject.Web.Mvc is an extension for ninject which providing integration with ASP.NET MVC.Controller constructors and dependencies of NerdDinner application Listing 1 – Constructor of DinnersController  public DinnersController(IDinnerRepository repository) {     dinnerRepository = repository; }  Listing 2 – Constrcutor of AccountControllerpublic AccountController(IFormsAuthentication formsAuth, IMembershipService service) {     FormsAuth = formsAuth ?? new FormsAuthenticationService();     MembershipService = service ?? new AccountMembershipService(); }  Listing 3 – Constructor of AccountMembership – Concrete class of IMembershipService public AccountMembershipService(MembershipProvider provider) {     _provider = provider ?? Membership.Provider; }    Dependencies of NerdDinnerDinnersController, RSVPController SearchController and ServicesController have a dependency with IDinnerRepositiry. The concrete implementation of IDinnerRepositiry is DinnerRepositiry. AccountController has dependencies with IFormsAuthentication and IMembershipService. The concrete implementation of IFormsAuthentication is FormsAuthenticationService and the concrete implementation of IMembershipService is AccountMembershipService. The AccountMembershipService has a dependency with ASP.NET Membership Provider. Dependency Injection in NerdDinner using NinjectThe below steps will configure Ninject to apply controller injection in NerdDinner application.Step 1 – Add reference for NinjectOpen the  NerdDinner application and add  reference to Ninject.dll and Ninject.Web.Mvc.dll. Both are available from http://github.com/enkari/ninject and http://github.com/enkari/ninject.web.mvcStep 2 – Extend HttpApplication with NinjectHttpApplication Ninject.Web.Mvc extension allows integration between the Ninject and ASP.NET MVC. For this, you have to extend your HttpApplication with NinjectHttpApplication. Open the Global.asax.cs and inherit your MVC application from  NinjectHttpApplication instead of HttpApplication.   public class MvcApplication : NinjectHttpApplication Then the Application_Start method should be replace with OnApplicationStarted method. Inside the OnApplicationStarted method, call the RegisterAllControllersIn() method.   protected override void OnApplicationStarted() {     AreaRegistration.RegisterAllAreas();     RegisterRoutes(RouteTable.Routes);     ViewEngines.Engines.Clear();     ViewEngines.Engines.Add(new MobileCapableWebFormViewEngine());     RegisterAllControllersIn(Assembly.GetExecutingAssembly()); }  The RegisterAllControllersIn method will enables to activating all controllers through Ninject in the assembly you have supplied .We are passing the current assembly as parameter for RegisterAllControllersIn() method. Now we can expose dependencies of controller constructors and properties to request injectionsStep 3 – Create Ninject ModulesWe can configure your dependency injection mapping information using Ninject Modules.Modules just need to implement the INinjectModule interface, but most should extend the NinjectModule class for simplicity. internal class ServiceModule : NinjectModule {     public override void Load()     {                    Bind<IFormsAuthentication>().To<FormsAuthenticationService>();         Bind<IMembershipService>().To<AccountMembershipService>();                  Bind<MembershipProvider>().ToConstant(Membership.Provider);         Bind<IDinnerRepository>().To<DinnerRepository>();     } } The above Binding inforamtion specified in the Load method tells the Ninject container that, to inject instance of DinnerRepositiry when there is a request for IDinnerRepositiry and  inject instance of FormsAuthenticationService when there is a request for IFormsAuthentication and inject instance of AccountMembershipService when there is a request for IMembershipService. The AccountMembershipService class has a dependency with ASP.NET Membership provider. So we configure that inject the instance of Membership Provider. When configuring the binding information, you can specify the object scope in you application.There are four built-in scopes available in Ninject:Transient  -  A new instance of the type will be created each time one is requested. (This is the default scope). Binding method is .InTransientScope()   Singleton - Only a single instance of the type will be created, and the same instance will be returned for each subsequent request. Binding method is .InSingletonScope()Thread -  One instance of the type will be created per thread. Binding method is .InThreadScope() Request -  One instance of the type will be created per web request, and will be destroyed when the request ends. Binding method is .InRequestScope() Step 4 – Configure the Ninject KernelOnce you create NinjectModule, you load them into a container called the kernel. To request an instance of a type from Ninject, you call the Get() extension method. We can configure the kernel, through the CreateKernel method in the Global.asax.cs. protected override IKernel CreateKernel() {     var modules = new INinjectModule[]     {         new ServiceModule()     };       return new StandardKernel(modules); } Here we are loading the Ninject Module (ServiceModule class created in the step 3)  onto the container called the kernel for performing dependency injection.Source CodeYou can download the source code from http://nerddinneraddons.codeplex.com. I just put the modified source code onto CodePlex repository. The repository will update with more add-ons for the NerdDinner application.

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• HttpContext.Items and Server.Transfer/Execute

  - by Rick Strahl

  A few days ago my buddy Ben Jones pointed out that he ran into a bug in the ScriptContainer control in the West Wind Web and Ajax Toolkit. The problem was basically that when a Server.Transfer call was applied the script container (and also various ClientScriptProxy script embedding routines) would potentially fail to load up the specified scripts. It turns out the problem is due to the fact that the various components in the toolkit use request specific singletons via a Current property. I use a static Current property tied to a Context.Items[] entry to handle this type of operation which looks something like this: /// <summary> /// Current instance of this class which should always be used to /// access this object. There are no public constructors to /// ensure the reference is used as a Singleton to further /// ensure that all scripts are written to the same clientscript /// manager. /// </summary> public static ClientScriptProxy Current { get { if (HttpContext.Current == null) return new ClientScriptProxy(); ClientScriptProxy proxy = null; if (HttpContext.Current.Items.Contains(STR_CONTEXTID)) proxy = HttpContext.Current.Items[STR_CONTEXTID] as ClientScriptProxy; else { proxy = new ClientScriptProxy(); HttpContext.Current.Items[STR_CONTEXTID] = proxy; } return proxy; } } The proxy is attached to a Context.Items[] item which makes the instance Request specific. This works perfectly fine in most situations EXCEPT when you’re dealing with Server.Transfer/Execute requests. Server.Transfer doesn’t cause Context.Items to be cleared so both the current transferred request and the original request’s Context.Items collection apply. For the ClientScriptProxy this causes a problem because script references are tracked on a per request basis in Context.Items to check for script duplication. Once a script is rendered an ID is written into the Context collection and so considered ‘rendered’: // No dupes - ref script include only once if (HttpContext.Current.Items.Contains( STR_SCRIPTITEM_IDENTITIFIER + fileId ) ) return; HttpContext.Current.Items.Add(STR_SCRIPTITEM_IDENTITIFIER + fileId, string.Empty); where the fileId is the script name or unique identifier. The problem is on the Transferred page the item will already exist in Context and so fail to render because it thinks the script has already rendered based on the Context item. Bummer. The workaround for this is simple once you know what’s going on, but in this case it was a bitch to track down because the context items are used in many places throughout this class. The trick is to determine when a request is transferred and then removing the specific keys. The first issue is to determine if a script is in a Trransfer or Execute call: if (HttpContext.Current.CurrentHandler != HttpContext.Current.Handler) Context.Handler is the original handler and CurrentHandler is the actual currently executing handler that is running when a Transfer/Execute is active. You can also use Context.PreviousHandler to get the last handler and chain through the whole list of handlers applied if Transfer calls are nested (dog help us all for the person debugging that). For the ClientScriptProxy the full logic to check for a transfer and remove the code looks like this: /// <summary> /// Clears all the request specific context items which are script references /// and the script placement index. /// </summary> public void ClearContextItemsOnTransfer() { if (HttpContext.Current != null) { // Check for Server.Transfer/Execute calls - we need to clear out Context.Items if (HttpContext.Current.CurrentHandler != HttpContext.Current.Handler) { List<string> Keys = HttpContext.Current.Items.Keys.Cast<string>().Where(s => s.StartsWith(STR_SCRIPTITEM_IDENTITIFIER) || s == STR_ScriptResourceIndex).ToList(); foreach (string key in Keys) { HttpContext.Current.Items.Remove(key); } } } } along with a small update to the Current property getter that sets a global flag to indicate whether the request was transferred: if (!proxy.IsTransferred && HttpContext.Current.Handler != HttpContext.Current.CurrentHandler) { proxy.ClearContextItemsOnTransfer(); proxy.IsTransferred = true; } return proxy; I know this is pretty ugly, but it works and it’s actually minimal fuss without affecting the behavior of the rest of the class. Ben had a different solution that involved explicitly clearing out the Context items and replacing the collection with a manually maintained list of items which also works, but required changes through the code to make this work. In hindsight, it would have been better to use a single object that encapsulates all the ‘persisted’ values and store that object in Context instead of all these individual small morsels. Hindsight is always 20/20 though :-}. If possible use Page.Items ClientScriptProxy is a generic component that can be used from anywhere in ASP.NET, so there are various methods that are not Page specific on this component which is why I used Context.Items, rather than the Page.Items collection.Page.Items would be a better choice since it will sidestep the above Server.Transfer nightmares as the Page is reloaded completely and so any new Page gets a new Items collection. No fuss there. So for the ScriptContainer control, which has to live on the page the behavior is a little different. It is attached to Page.Items (since it’s a control): /// <summary> /// Returns a current instance of this control if an instance /// is already loaded on the page. Otherwise a new instance is /// created, added to the Form and returned. /// /// It's important this function is not called too early in the /// page cycle - it should not be called before Page.OnInit(). /// /// This property is the preferred way to get a reference to a /// ScriptContainer control that is either already on a page /// or needs to be created. Controls in particular should always /// use this property. /// </summary> public static ScriptContainer Current { get { // We need a context for this to work! if (HttpContext.Current == null) return null; Page page = HttpContext.Current.CurrentHandler as Page; if (page == null) throw new InvalidOperationException(Resources.ERROR_ScriptContainer_OnlyWorks_With_PageBasedHandlers); ScriptContainer ctl = null; // Retrieve the current instance ctl = page.Items[STR_CONTEXTID] as ScriptContainer; if (ctl != null) return ctl; ctl = new ScriptContainer(); page.Form.Controls.Add(ctl); return ctl; } } The biggest issue with this approach is that you have to explicitly retrieve the page in the static Current property. Notice again the use of CurrentHandler (rather than Handler which was my original implementation) to ensure you get the latest page including the one that Server.Transfer fired. Server.Transfer and Server.Execute are Evil All that said – this fix is probably for the 2 people who are crazy enough to rely on Server.Transfer/Execute. :-} There are so many weird behavior problems with these commands that I avoid them at all costs. I don’t think I have a single application that uses either of these commands… Related Resources Full source of ClientScriptProxy.cs (repository) Part of the West Wind Web Toolkit Static Singletons for ASP.NET Controls Post © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  

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• BNF – how to read syntax?

  - by Piotr Rodak

  A few days ago I read post of Jen McCown (blog) about her idea of blogging about random articles from Books Online. I think this is a great idea, even if Jen says that it’s not exciting or sexy. I noticed that many of the questions that appear on forums and other media arise from pure fact that people asking questions didn’t bother to read and understand the manual – Books Online. Jen came up with a brilliant, concise acronym that describes very well the category of posts about Books Online – RTFM365. I take liberty of tagging this post with the same acronym. I often come across questions of type – ‘Hey, i am trying to create a table, but I am getting an error’. The error often says that the syntax is invalid. 1 CREATE TABLE dbo.Employees 2 (guid uniqueidentifier CONSTRAINT DEFAULT Guid_Default NEWSEQUENTIALID() ROWGUIDCOL, 3 Employee_Name varchar(60) 4 CONSTRAINT Guid_PK PRIMARY KEY (guid) ); 5 The answer is usually(1), ‘Ok, let me check it out.. Ah yes – you have to put name of the DEFAULT constraint before the type of constraint: 1 CREATE TABLE dbo.Employees 2 (guid uniqueidentifier CONSTRAINT Guid_Default DEFAULT NEWSEQUENTIALID() ROWGUIDCOL, 3 Employee_Name varchar(60) 4 CONSTRAINT Guid_PK PRIMARY KEY (guid) ); Why many people stumble on syntax errors? Is the syntax poorly documented? No, the issue is, that correct syntax of the CREATE TABLE statement is documented very well in Books Online and is.. intimidating. Many people can be taken aback by the rather complex block of code that describes all intricacies of the statement. However, I don’t know better way of defining syntax of the statement or command. The notation that is used to describe syntax in Books Online is a form of Backus-Naur notatiion, called BNF for short sometimes. This is a notation that was invented around 50 years ago, and some say that even earlier, around 400 BC – would you believe? Originally it was used to define syntax of, rather ancient now, ALGOL programming language (in 1950’s, not in ancient India). If you look closer at the definition of the BNF, it turns out that the principles of this syntax are pretty simple. Here are a few bullet points: italic_text is a placeholder for your identifier <italic_text_in_angle_brackets> is a definition which is described further. [everything in square brackets] is optional {everything in curly brackets} is obligatory everything | separated | by | operator is an alternative ::= “assigns” definition to an identifier Yes, it looks like these six simple points give you the key to understand even the most complicated syntax definitions in Books Online. Books Online contain an article about syntax conventions – have you ever read it? Let’s have a look at fragment of the CREATE TABLE statement: 1 CREATE TABLE 2 [ database_name . [ schema_name ] . | schema_name . ] table_name 3 ( { <column_definition> | <computed_column_definition> 4 | <column_set_definition> } 5 [ <table_constraint> ] [ ,...n ] ) 6 [ ON { partition_scheme_name ( partition_column_name ) | filegroup 7 | "default" } ] 8 [ { TEXTIMAGE_ON { filegroup | "default" } ] 9 [ FILESTREAM_ON { partition_scheme_name | filegroup 10 | "default" } ] 11 [ WITH ( <table_option> [ ,...n ] ) ] 12 [ ; ] Let’s look at line 2 of the above snippet: This line uses rules 3 and 5 from the list. So you know that you can create table which has specified one of the following. just name – table will be created in default user schema schema name and table name – table will be created in specified schema database name, schema name and table name – table will be created in specified database, in specified schema database name, .., table name – table will be created in specified database, in default schema of the user. Note that this single line of the notation describes each of the naming schemes in deterministic way. The ‘optionality’ of the schema_name element is nested within database_name.. section. You can use either database_name and optional schema name, or just schema name – this is specified by the pipe character ‘|’. The error that user gets with execution of the first script fragment in this post is as follows: Msg 156, Level 15, State 1, Line 2 Incorrect syntax near the keyword 'DEFAULT'. Ok, let’s have a look how to find out the correct syntax. Line number 3 of the BNF fragment above contains reference to <column_definition>. Since column_definition is in angle brackets, we know that this is a reference to notion described further in the code. And indeed, the very next fragment of BNF contains syntax of the column definition. 1 <column_definition> ::= 2 column_name <data_type> 3 [ FILESTREAM ] 4 [ COLLATE collation_name ] 5 [ NULL | NOT NULL ] 6 [ 7 [ CONSTRAINT constraint_name ] DEFAULT constant_expression ] 8 | [ IDENTITY [ ( seed ,increment ) ] [ NOT FOR REPLICATION ] 9 ] 10 [ ROWGUIDCOL ] [ <column_constraint> [ ...n ] ] 11 [ SPARSE ] Look at line 7 in the above fragment. It says, that the column can have a DEFAULT constraint which, if you want to name it, has to be prepended with [CONSTRAINT constraint_name] sequence. The name of the constraint is optional, but I strongly recommend you to make the effort of coming up with some meaningful name yourself. So the correct syntax of the CREATE TABLE statement from the beginning of the article is like this: 1 CREATE TABLE dbo.Employees 2 (guid uniqueidentifier CONSTRAINT Guid_Default DEFAULT NEWSEQUENTIALID() ROWGUIDCOL, 3 Employee_Name varchar(60) 4 CONSTRAINT Guid_PK PRIMARY KEY (guid) ); That is practically everything you should know about BNF. I encourage you to study the syntax definitions for various statements and commands in Books Online, you can find really interesting things hidden there. Technorati Tags: SQL Server,t-sql,BNF,syntax   (1) No, my answer usually is a question – ‘What error message? What does it say?’. You’d be surprised to know how many people think I can go through time and space and look at their screen at the moment they received the error.

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• Monitor your Hard Drive’s Health with Acronis Drive Monitor

  - by Matthew Guay

  Are you worried that your computer’s hard drive could die without any warning?  Here’s how you can keep tabs on it and get the first warning signs of potential problems before you actually lose your critical data. Hard drive failures are one of the most common ways people lose important data from their computers.  As more of our memories and important documents are stored digitally, a hard drive failure can mean the loss of years of work.  Acronis Drive Monitor helps you avert these disasters by warning you at the first signs your hard drive may be having trouble.  It monitors many indicators, including heat, read/write errors, total lifespan, and more. It then notifies you via a taskbar popup or email that problems have been detected.  This early warning lets you know ahead of time that you may need to purchase a new hard drive and migrate your data before it’s too late. Getting Started Head over to the Acronis site to download Drive Monitor (link below).  You’ll need to enter your name and email, and then you can download this free tool. Also, note that the download page may ask if you want to include a trial of their for-pay backup program.  If you wish to simply install the Drive Monitor utility, click Continue without adding. Run the installer when the download is finished.  Follow the prompts and install as normal. Once it’s installed, you can quickly get an overview of your hard drives’ health.  Note that it shows 3 categories: Disk problems, Acronis backup, and Critical Events.  On our computer, we had Seagate DiskWizard, an image backup utility based on Acronis Backup, installed, and Acronis detected it. Drive Monitor stays running in your tray even when the application window is closed.  It will keep monitoring your hard drives, and will alert you if there’s a problem. Find Detailed Information About Your Hard Drives Acronis’ simple interface lets you quickly see an overview of how the drives on your computer are performing.  If you’d like more information, click the link under the description.  Here we see that one of our drives have overheated, so click Show disks to get more information. Now you can select each of your drives and see more information about them.  From the Disk overview tab that opens by default, we see that our drive is being monitored, has been running for a total of 368 days, and that it’s health is good.  However, it is running at 113F, which is over the recommended max of 107F.   The S.M.A.R.T. parameters tab gives us more detailed information about our drive.  Most users wouldn’t know what an accepted value would be, so it also shows the status.  If the value is within the accepted parameters, it will report OK; otherwise, it will show that has a problem in this area. One very interesting piece of information we can see is the total number of Power-On Hours, Start/Stop Count, and Power Cycle Count.  These could be useful indicators to check if you’re considering purchasing a second hand computer.  Simply load this program, and you’ll get a better view of how long it’s been in use. Finally, the Events tab shows each time the program gave a warning.  We can see that our drive, which had been acting flaky already, is routinely overheating even when our other hard drive was running in normal temperature ranges. Monitor Acronis Backups And Critical Errors In addition to monitoring critical stats of your hard drives, Acronis Drive Monitor also keeps up with the status of your backup software and critical events reported by Windows.  You can access these from the front page, or via the links on the left hand sidebar.  If you have any edition of any Acronis Backup product installed, it will show that it was detected.  Note that it can only monitor the backup status of the newest versions of Acronis Backup and True Image. If no Acronis backup software was installed, it will show a warning that the drive may be unprotected and will give you a link to download Acronis backup software.   If you have another backup utility installed that you wish to monitor yourself, click Configure backup monitoring, and then disable monitoring on the drives you’re monitoring yourself. Finally, you can view any detected Critical events from the Critical events tab on the left. Get Emailed When There’s a Problem One of Drive Monitor’s best features is the ability to send you an email whenever there’s a problem.  Since this program can run on any version of Windows, including the Server and Home Server editions, you can use this feature to stay on top of your hard drives’ health even when you’re not nearby.  To set this up, click Options in the top left corner. Select Alerts on the left, and then click the Change settings link to setup your email account. Enter the email address which you wish to receive alerts, and a name for the program.  Then, enter the outgoing mail server settings for your email.  If you have a Gmail account, enter the following information: Outgoing mail server (SMTP): smtp.gmail.com Port: 587 Username and Password: Your gmail address and password Check the Use encryption box, and then select TLS from the encryption options.   It will now send a test message to your email account, so check and make sure it sent ok. Now you can choose to have the program automatically email you when warnings and critical alerts appear, and also to have it send regular disk status reports.   Conclusion Whether you’ve got a brand new hard drive or one that’s seen better days, knowing the real health of your it is one of the best ways to be prepared before disaster strikes.  It’s no substitute for regular backups, but can help you avert problems.  Acronis Drive Monitor is a nice tool for this, and although we wish it wasn’t so centered around their backup offerings, we still found it a nice tool. Link Download Acronis Drive Monitor (registration required) Similar Articles Productive Geek Tips Quick Tip: Change Monitor Timeout From Command LineAnalyze and Manage Hard Drive Space with WinDirStatMonitor CPU, Memory, and Disk IO In Windows 7 with Taskbar MetersDefrag Multiple Hard Drives At Once In WindowsFind Your Missing USB Drive on Windows XP TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips HippoRemote Pro 2.2 Xobni Plus for Outlook All My Movies 5.9 CloudBerry Online Backup 1.5 for Windows Home Server Windows 7’s WordPad is Actually Good Greate Image Viewing and Management with Zoner Photo Studio Free Windows Media Player Plus! – Cool WMP Enhancer Get Your Team’s World Cup Schedule In Google Calendar Backup Drivers With Driver Magician TubeSort: YouTube Playlist Organizer

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• What's up with LDoms: Part 4 - Virtual Networking Explained

  - by Stefan Hinker

  I'm back from my summer break (and some pressing business that kept me away from this), ready to continue with Oracle VM Server for SPARC ;-) In this article, we'll have a closer look at virtual networking.  Basic connectivity as we've seen it in the first, simple example, is easy enough.  But there are numerous options for the virtual switches and virtual network ports, which we will discuss in more detail now.   In this section, we will concentrate on virtual networking - the capabilities of virtual switches and virtual network ports - only.  Other options involving hardware assignment or redundancy will be covered in separate sections later on. There are two basic components involved in virtual networking for LDoms: Virtual switches and virtual network devices.  The virtual switch should be seen just like a real ethernet switch.  It "runs" in the service domain and moves ethernet packets back and forth.  A virtual network device is plumbed in the guest domain.  It corresponds to a physical network device in the real world.  There, you'd be plugging a cable into the network port, and plug the other end of that cable into a switch.  In the virtual world, you do the same:  You create a virtual network device for your guest and connect it to a virtual switch in a service domain.  The result works just like in the physical world, the network device sends and receives ethernet packets, and the switch does all those things ethernet switches tend to do. If you look at the reference manual of Oracle VM Server for SPARC, there are numerous options for virtual switches and network devices.  Don't be confused, it's rather straight forward, really.  Let's start with the simple case, and work our way to some more sophisticated options later on.  In many cases, you'll want to have several guests that communicate with the outside world on the same ethernet segment.  In the real world, you'd connect each of these systems to the same ethernet switch.  So, let's do the same thing in the virtual world: root@sun # ldm add-vsw net-dev=nxge2 admin-vsw primary root@sun # ldm add-vnet admin-net admin-vsw mars root@sun # ldm add-vnet admin-net admin-vsw venus We've just created a virtual switch called "admin-vsw" and connected it to the physical device nxge2.  In the physical world, we'd have powered up our ethernet switch and installed a cable between it and our big enterprise datacenter switch.  We then created a virtual network interface for each one of the two guest systems "mars" and "venus" and connected both to that virtual switch.  They can now communicate with each other and with any system reachable via nxge2.  If primary were running Solaris 10, communication with the guests would not be possible.  This is different with Solaris 11, please see the Admin Guide for details.  Note that I've given both the vswitch and the vnet devices some sensible names, something I always recommend. Unless told otherwise, the LDoms Manager software will automatically assign MAC addresses to all network elements that need one.  It will also make sure that these MAC addresses are unique and reuse MAC addresses to play nice with all those friendly DHCP servers out there.  However, if we want to do this manually, we can also do that.  (One reason might be firewall rules that work on MAC addresses.)  So let's give mars a manually assigned MAC address: root@sun # ldm set-vnet mac-addr=0:14:4f:f9:c4:13 admin-net mars Within the guest, these virtual network devices have their own device driver.  In Solaris 10, they'd appear as "vnet0".  Solaris 11 would apply it's usual vanity naming scheme.  We can configure these interfaces just like any normal interface, give it an IP-address and configure sophisticated routing rules, just like on bare metal.  In many cases, using Jumbo Frames helps increase throughput performance.  By default, these interfaces will run with the standard ethernet MTU of 1500 bytes.  To change this,  it is usually sufficient to set the desired MTU for the virtual switch.  This will automatically set the same MTU for all vnet devices attached to that switch.  Let's change the MTU size of our admin-vsw from the example above: root@sun # ldm set-vsw mtu=9000 admin-vsw primary Note that that you can set the MTU to any value between 1500 and 16000.  Of course, whatever you set needs to be supported by the physical network, too. Another very common area of network configuration is VLAN tagging. This can be a little confusing - my advise here is to be very clear on what you want, and perhaps draw a little diagram the first few times.  As always, keeping a configuration simple will help avoid errors of all kind.  Nevertheless, VLAN tagging is very usefull to consolidate different networks onto one physical cable.  And as such, this concept needs to be carried over into the virtual world.  Enough of the introduction, here's a little diagram to help in explaining how VLANs work in LDoms: Let's remember that any VLANs not explicitly tagged have the default VLAN ID of 1. In this example, we have a vswitch connected to a physical network that carries untagged traffic (VLAN ID 1) as well as VLANs 11, 22, 33 and 44.  There might also be other VLANs on the wire, but the vswitch will ignore all those packets.  We also have two vnet devices, one for mars and one for venus.  Venus will see traffic from VLANs 33 and 44 only.  For VLAN 44, venus will need to configure a tagged interface "vnet44000".  For VLAN 33, the vswitch will untag all incoming traffic for venus, so that venus will see this as "normal" or untagged ethernet traffic.  This is very useful to simplify guest configuration and also allows venus to perform Jumpstart or AI installations over this network even if the Jumpstart or AI server is connected via VLAN 33.  Mars, on the other hand, has full access to untagged traffic from the outside world, and also to VLANs 11,22 and 33, but not 44.  On the command line, we'd do this like this: root@sun # ldm add-vsw net-dev=nxge2 pvid=1 vid=11,22,33,44 admin-vsw primary root@sun # ldm add-vnet admin-net pvid=1 vid=11,22,33 admin-vsw mars root@sun # ldm add-vnet admin-net pvid=33 vid=44 admin-vsw venus Finally, I'd like to point to a neat little option that will make your live easier in all those cases where configurations tend to change over the live of a guest system.  It's the "id=<somenumber>" option available for both vswitches and vnet devices.  Normally, Solaris in the guest would enumerate network devices sequentially.  However, it has ways of remembering this initial numbering.  This is good in the physical world.  In the virtual world, whenever you unbind (aka power off and disassemble) a guest system, remove and/or add network devices and bind the system again, chances are this numbering will change.  Configuration confusion will follow suit.  To avoid this, nail down the initial numbering by assigning each vnet device it's device-id explicitly: root@sun # ldm add-vnet admin-net id=1 admin-vsw venus Please consult the Admin Guide for details on this, and how to decipher these network ids from Solaris running in the guest. Thanks for reading this far.  Links for further reading are essentially only the Admin Guide and Reference Manual and can be found above.  I hope this is useful and, as always, I welcome any comments.

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• SQL SERVER – Extending SQL Azure with Azure worker role – Guest Post by Paras Doshi

  - by pinaldave

  This is guest post by Paras Doshi. Paras Doshi is a research Intern at SolidQ.com and a Microsoft student partner. He is currently working in the domain of SQL Azure. SQL Azure is nothing but a SQL server in the cloud. SQL Azure provides benefits such as on demand rapid provisioning, cost-effective scalability, high availability and reduced management overhead. To see an introduction on SQL Azure, check out the post by Pinal here In this article, we are going to discuss how to extend SQL Azure with the Azure worker role. In other words, we will attempt to write a custom code and host it in the Azure worker role; the aim is to add some features that are not available with SQL Azure currently or features that need to be customized for flexibility. This way we extend the SQL Azure capability by building some solutions that run on Azure as worker roles. To understand Azure worker role, think of it as a windows service in cloud. Azure worker role can perform background processes, and to handle processes such as synchronization and backup, it becomes our ideal tool. First, we will focus on writing a worker role code that synchronizes SQL Azure databases. Before we do so, let’s see some scenarios in which synchronization between SQL Azure databases is beneficial: scaling out access over multiple databases enables us to handle workload efficiently As of now, SQL Azure database can be hosted in one of any six datacenters. By synchronizing databases located in different data centers, one can extend the data by enabling access to geographically distributed data Let us see some scenarios in which SQL server to SQL Azure database synchronization is beneficial To backup SQL Azure database on local infrastructure Rather than investing in local infrastructure for increased workloads, such workloads could be handled by cloud Ability to extend data to different datacenters located across the world to enable efficient data access from remote locations Now, let us develop cloud-based app that synchronizes SQL Azure databases. For an Introduction to developing cloud based apps, click here Now, in this article, I aim to provide a bird’s eye view of how a code that synchronizes SQL Azure databases look like and then list resources that can help you develop the solution from scratch. Now, if you newly add a worker role to the cloud-based project, this is how the code will look like. (Note: I have added comments to the skeleton code to point out the modifications that will be required in the code to carry out the SQL Azure synchronization. Note the placement of Setup() and Sync() function.) Click here (http://parasdoshi1989.files.wordpress.com/2011/06/code-snippet-1-for-extending-sql-azure-with-azure-worker-role1.pdf ) Enabling SQL Azure databases synchronization through sync framework is a two-step process. In the first step, the database is provisioned and sync framework creates tracking tables, stored procedures, triggers, and tables to store metadata to enable synchronization. This is one time step. The code for the same is put in the setup() function which is called once when the worker role starts. Now, the second step is continuous (or on demand) synchronization of SQL Azure databases by propagating changes between databases. This is done on a continuous basis by calling the sync() function in the while loop. The code logic to synchronize changes between SQL Azure databases should be put in the sync() function. Discussing the coding part step by step is out of the scope of this article. Therefore, let me suggest you a resource, which is given here. Also, note that before you start developing the code, you will need to install SYNC framework 2.1 SDK (download here). Further, you will reference some libraries before you start coding. Details regarding the same are available in the article that I just pointed to. You will be charged for data transfers if the databases are not in the same datacenter. For pricing information, go here Currently, a tool named DATA SYNC, which is built on top of sync framework, is available in CTP that allows SQL Azure <-> SQL server and SQL Azure <-> SQL Azure synchronization (without writing single line of code); however, in some cases, the custom code shown in this blogpost provides flexibility that is not available with Data SYNC. For instance, filtering is not supported in the SQL Azure DATA SYNC CTP2; if you wish to have such a functionality now, then you have the option of developing a custom code using SYNC Framework. Now, this code can be easily extended to synchronize at some schedule. Let us say we want the databases to get synchronized every day at 10:00 pm. This is what the code will look like now: (http://parasdoshi1989.files.wordpress.com/2011/06/code-snippet-2-for-extending-sql-azure-with-azure-worker-role.pdf) Don’t you think that by writing such a code, we are imitating the functionality provided by the SQL server agent for a SQL server? Think about it. We are scheduling our administrative task by writing custom code – in other words, we have developed a “Light weight SQL server agent for SQL Azure!” Since the SQL server agent is not currently available in cloud, we have developed a solution that enables us to schedule tasks, and thus we have extended SQL Azure with the Azure worker role! Now if you wish to track jobs, you can do so by storing this data in SQL Azure (or Azure tables). The reason is that Windows Azure is a stateless platform, and we will need to store the state of the job ourselves and the choice that you have is SQL Azure or Azure tables. Note that this solution requires custom code and also it is not UI driven; however, for now, it can act as a temporary solution until SQL server agent is made available in the cloud. Moreover, this solution does not encompass functionalities that a SQL server agent provides, but it does open up an interesting avenue to schedule some of the tasks such as backup and synchronization of SQL Azure databases by writing some custom code in the Azure worker role. Now, let us see one more possibility – i.e., running BCP through a worker role in Azure-hosted services and then uploading the backup files either locally or on blobs. If you upload it locally, then consider the data transfer cost. If you upload it to blobs residing in the same datacenter, then no transfer cost applies but the cost on blob size applies. So, before choosing the option, you need to evaluate your preferences keeping the cost associated with each option in mind. In this article, I have shown that Azure worker role solution could be developed to synchronize SQL Azure databases. Moreover, a light-weight SQL server agent for SQL Azure can be developed. Also we discussed the possibility of running BCP through a worker role in Azure-hosted services for backing up our precious SQL Azure data. Thus, we can extend SQL Azure with the Azure worker role. But remember: you will be charged for running Azure worker roles. So at the end of the day, you need to ask – am I willing to build a custom code and pay money to achieve this functionality? I hope you found this blog post interesting. If you have any questions/feedback, you can comment below or you can mail me at Paras[at]student-partners[dot]com Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Azure, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL Monitor’s data repository

  - by Chris Lambrou

  As one of the developers of SQL Monitor, I often get requests passed on by our support people from customers who are looking to dip into SQL Monitor’s own data repository, in order to pull out bits of information that they’re interested in. Since there’s clearly interest out there in playing around directly with the data repository, I thought I’d write some blog posts to start to describe how it all works. The hardest part for me is knowing where to begin, since the schema of the data repository is pretty big. Hmmm… I guess it’s tricky for anyone to write anything but the most trivial of queries against the data repository without understanding the hierarchy of monitored objects, so perhaps my first post should start there. I always imagine that whenever a customer fires up SSMS and starts to explore their SQL Monitor data repository database, they become immediately bewildered by the schema – that was certainly my experience when I did so for the first time. The following query shows the number of different object types in the data repository schema: SELECT type_desc, COUNT(*) AS [count] FROM sys.objects GROUP BY type_desc ORDER BY type_desc;  type_desccount 1DEFAULT_CONSTRAINT63 2FOREIGN_KEY_CONSTRAINT181 3INTERNAL_TABLE3 4PRIMARY_KEY_CONSTRAINT190 5SERVICE_QUEUE3 6SQL_INLINE_TABLE_VALUED_FUNCTION381 7SQL_SCALAR_FUNCTION2 8SQL_STORED_PROCEDURE100 9SYSTEM_TABLE41 10UNIQUE_CONSTRAINT54 11USER_TABLE193 12VIEW124 With 193 tables, 124 views, 100 stored procedures and 381 table valued functions, that’s quite a hefty schema, and when you browse through it using SSMS, it can be a bit daunting at first. So, where to begin? Well, let’s narrow things down a bit and only look at the tables belonging to the data schema. That’s where all of the collected monitoring data is stored by SQL Monitor. The following query gives us the names of those tables: SELECT sch.name + '.' + obj.name AS [name] FROM sys.objects obj JOIN sys.schemas sch ON sch.schema_id = obj.schema_id WHERE obj.type_desc = 'USER_TABLE' AND sch.name = 'data' ORDER BY sch.name, obj.name; This query still returns 110 tables. I won’t show them all here, but let’s have a look at the first few of them:  name 1data.Cluster_Keys 2data.Cluster_Machine_ClockSkew_UnstableSamples 3data.Cluster_Machine_Cluster_StableSamples 4data.Cluster_Machine_Keys 5data.Cluster_Machine_LogicalDisk_Capacity_StableSamples 6data.Cluster_Machine_LogicalDisk_Keys 7data.Cluster_Machine_LogicalDisk_Sightings 8data.Cluster_Machine_LogicalDisk_UnstableSamples 9data.Cluster_Machine_LogicalDisk_Volume_StableSamples 10data.Cluster_Machine_Memory_Capacity_StableSamples 11data.Cluster_Machine_Memory_UnstableSamples 12data.Cluster_Machine_Network_Capacity_StableSamples 13data.Cluster_Machine_Network_Keys 14data.Cluster_Machine_Network_Sightings 15data.Cluster_Machine_Network_UnstableSamples 16data.Cluster_Machine_OperatingSystem_StableSamples 17data.Cluster_Machine_Ping_UnstableSamples 18data.Cluster_Machine_Process_Instances 19data.Cluster_Machine_Process_Keys 20data.Cluster_Machine_Process_Owner_Instances 21data.Cluster_Machine_Process_Sightings 22data.Cluster_Machine_Process_UnstableSamples 23… There are two things I want to draw your attention to: The table names describe a hierarchy of the different types of object that are monitored by SQL Monitor (e.g. clusters, machines and disks). For each object type in the hierarchy, there are multiple tables, ending in the suffixes _Keys, _Sightings, _StableSamples and _UnstableSamples. Not every object type has a table for every suffix, but the _Keys suffix is especially important and a _Keys table does indeed exist for every object type. In fact, if we limit the query to return only those tables ending in _Keys, we reveal the full object hierarchy: SELECT sch.name + '.' + obj.name AS [name] FROM sys.objects obj JOIN sys.schemas sch ON sch.schema_id = obj.schema_id WHERE obj.type_desc = 'USER_TABLE' AND sch.name = 'data' AND obj.name LIKE '%_Keys' ORDER BY sch.name, obj.name;  name 1data.Cluster_Keys 2data.Cluster_Machine_Keys 3data.Cluster_Machine_LogicalDisk_Keys 4data.Cluster_Machine_Network_Keys 5data.Cluster_Machine_Process_Keys 6data.Cluster_Machine_Services_Keys 7data.Cluster_ResourceGroup_Keys 8data.Cluster_ResourceGroup_Resource_Keys 9data.Cluster_SqlServer_Agent_Job_History_Keys 10data.Cluster_SqlServer_Agent_Job_Keys 11data.Cluster_SqlServer_Database_BackupType_Backup_Keys 12data.Cluster_SqlServer_Database_BackupType_Keys 13data.Cluster_SqlServer_Database_CustomMetric_Keys 14data.Cluster_SqlServer_Database_File_Keys 15data.Cluster_SqlServer_Database_Keys 16data.Cluster_SqlServer_Database_Table_Index_Keys 17data.Cluster_SqlServer_Database_Table_Keys 18data.Cluster_SqlServer_Error_Keys 19data.Cluster_SqlServer_Keys 20data.Cluster_SqlServer_Services_Keys 21data.Cluster_SqlServer_SqlProcess_Keys 22data.Cluster_SqlServer_TopQueries_Keys 23data.Cluster_SqlServer_Trace_Keys 24data.Group_Keys The full object type hierarchy looks like this: Cluster Machine LogicalDisk Network Process Services ResourceGroup Resource SqlServer Agent Job History Database BackupType Backup CustomMetric File Table Index Error Services SqlProcess TopQueries Trace Group Okay, but what about the individual objects themselves represented at each level in this hierarchy? Well that’s what the _Keys tables are for. This is probably best illustrated by way of a simple example – how can I query my own data repository to find the databases on my own PC for which monitoring data has been collected? Like this: SELECT clstr._Name AS cluster_name, srvr._Name AS instance_name, db._Name AS database_name FROM data.Cluster_SqlServer_Database_Keys db JOIN data.Cluster_SqlServer_Keys srvr ON db.ParentId = srvr.Id -- Note here how the parent of a Database is a Server JOIN data.Cluster_Keys clstr ON srvr.ParentId = clstr.Id -- Note here how the parent of a Server is a Cluster WHERE clstr._Name = 'dev-chrisl2' -- This is the hostname of my own PC ORDER BY clstr._Name, srvr._Name, db._Name;  cluster_nameinstance_namedatabase_name 1dev-chrisl2SqlMonitorData 2dev-chrisl2master 3dev-chrisl2model 4dev-chrisl2msdb 5dev-chrisl2mssqlsystemresource 6dev-chrisl2tempdb 7dev-chrisl2sql2005SqlMonitorData 8dev-chrisl2sql2005TestDatabase 9dev-chrisl2sql2005master 10dev-chrisl2sql2005model 11dev-chrisl2sql2005msdb 12dev-chrisl2sql2005mssqlsystemresource 13dev-chrisl2sql2005tempdb 14dev-chrisl2sql2008SqlMonitorData 15dev-chrisl2sql2008master 16dev-chrisl2sql2008model 17dev-chrisl2sql2008msdb 18dev-chrisl2sql2008mssqlsystemresource 19dev-chrisl2sql2008tempdb These results show that I have three SQL Server instances on my machine (a default instance, one named sql2005 and one named sql2008), and each instance has the usual set of system databases, along with a database named SqlMonitorData. Basically, this is where I test SQL Monitor on different versions of SQL Server, when I’m developing. There are a few important things we can learn from this query: Each _Keys table has a column named Id. This is the primary key. Each _Keys table has a column named ParentId. A foreign key relationship is defined between each _Keys table and its parent _Keys table in the hierarchy. There are two exceptions to this, Cluster_Keys and Group_Keys, because clusters and groups live at the root level of the object hierarchy. Each _Keys table has a column named _Name. This is used to uniquely identify objects in the table within the scope of the same shared parent object. Actually, that last item isn’t always true. In some cases, the _Name column is actually called something else. For example, the data.Cluster_Machine_Services_Keys table has a column named _ServiceName instead of _Name (sorry for the inconsistency). In other cases, a name isn’t sufficient to uniquely identify an object. For example, right now my PC has multiple processes running, all sharing the same name, Chrome (one for each tab open in my web-browser). In such cases, multiple columns are used to uniquely identify an object within the scope of the same shared parent object. Well, that’s it for now. I’ve given you enough information for you to explore the _Keys tables to see how objects are stored in your own data repositories. In a future post, I’ll try to explain how monitoring data is stored for each object, using the _StableSamples and _UnstableSamples tables. If you have any questions about this post, or suggestions for future posts, just submit them in the comments section below.

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• Building extensions for Expression Blend 4 using MEF

  - by Timmy Kokke

  Introduction Although it was possible to write extensions for Expression Blend and Expression Design, it wasn’t very easy and out of the box only one addin could be used. With Expression Blend 4 it is possible to write extensions using MEF, the Managed Extensibility Framework. Until today there’s no documentation on how to build these extensions, so look thru the code with Reflector is something you’ll have to do very often. Because Blend and Design are build using WPF searching the visual tree with Snoop and Mole belong to the tools you’ll be using a lot exploring the possibilities.  Configuring the extension project Extensions are regular .NET class libraries. To create one, load up Visual Studio 2010 and start a new project. Because Blend is build using WPF, choose a WPF User Control Library from the Windows section and give it a name and location. I named mine DemoExtension1. Because Blend looks for addins named *.extension.dll  you’ll have to tell Visual Studio to use that in the Assembly Name. To change the Assembly Name right click your project and go to Properties. On the Application tab, add .Extension to name already in the Assembly name text field. To be able to debug this extension, I prefer to set the output path on the Build tab to the extensions folder of Expression Blend. This means that everything that used to go into the Debug folder is placed in the extensions folder. Including all referenced assemblies that have the copy local property set to false. One last setting. To be able to debug your extension you could start Blend and attach the debugger by hand. I like it to be able to just hit F5. Go to the Debug tab and add the the full path to Blend.exe in the Start external program text field. Extension Class Add a new class to the project.  This class needs to be inherited from the IPackage interface. The IPackage interface can be found in the Microsoft.Expression.Extensibility namespace. To get access to this namespace add Microsoft.Expression.Extensibility.dll to your references. This file can be found in the same folder as the (Expression Blend 4 Beta) Blend.exe file. Make sure the Copy Local property is set to false in this reference. After implementing the interface the class would look something like: using Microsoft.Expression.Extensibility; namespace DemoExtension1 { public class DemoExtension1:IPackage { public void Load(IServices services) { } public void Unload() { } } } These two methods are called when your addin is loaded and unloaded. The parameter passed to the Load method, IServices services, is your main entry point into Blend. The IServices interface exposes the GetService<T> method. You will be using this method a lot. Almost every part of Blend can be accessed thru a service. For example, you can use to get to the commanding services of Blend by calling GetService<ICommandService>() or to get to the Windowing services by calling GetService<IWindowService>(). To get Blend to load the extension we have to implement MEF. (You can get up to speed on MEF on the community site or read the blog of Mr. MEF, Glenn Block.)  In the case of Blend extensions, all that needs to be done is mark the class with an Export attribute and pass it the type of IPackage. The Export attribute can be found in the System.ComponentModel.Composition namespace which is part of the .NET 4 framework. You need to add this to your references. using System.ComponentModel.Composition; using Microsoft.Expression.Extensibility;   namespace DemoExtension1 { [Export(typeof(IPackage))] public class DemoExtension1:IPackage { Blend is able to find your addin now. Adding UI The addin doesn’t do very much at this point. The WPF User Control Library came with a UserControl so lets use that in this example. I just drop a Button and a TextBlock onto the surface of the control to have something to show in the demo. To get the UserControl to work in Blend it has to be registered with the WindowService.  Call GetService<IWindowService>() on the IServices interface to get access to the windowing services. The UserControl will be used in Blend on a Palette and has to be registered to enable it. This is done by calling the RegisterPalette on the IWindowService interface and passing it an identifier, an instance of the UserControl and a caption for the palette. public void Load(IServices services) { IWindowService windowService = services.GetService<IWindowService>(); UserControl1 uc = new UserControl1(); windowService.RegisterPalette("DemoExtension", uc, "Demo Extension"); } After hitting F5 to start debugging Expression Blend will start. You should be able to find the addin in the Window menu now. Activating this window will show the “Demo Extension” palette with the UserControl, style according to the settings of Blend. Now what? Because little is publicly known about how to access different parts of Blend adding breakpoints in Debug mode and browsing thru objects using the Quick Watch feature of Visual Studio is something you have to do very often. This demo extension can be used for that purpose very easily. Add the click event handler to the button on the UserControl. Change the contructor to take the IServices interface and store this in a field. Set a breakpoint in the Button_Click method. public partial class UserControl1 : UserControl { private readonly IServices _services;   public UserControl1(IServices services) { _services = services; InitializeComponent(); }   private void button1_Click(object sender, RoutedEventArgs e) { } } Change the call to the constructor in the load method and pass it the services property. public void Load(IServices services) { IWindowService service = services.GetService<IWindowService>(); UserControl1 uc = new UserControl1(services); service.RegisterPalette("DemoExtension", uc, "Demo Extension"); } Hit F5 to compile and start Blend. Got to the window menu and start show the addin. Click on  the button to hit the breakpoint. Now place the carrot text _services text in the code window and hit Shift+F9 to show the Quick Watch window. Now start exploring and discovering where to find everything you need.  More Information The are no official resources available yet. Microsoft has released one extension for expression Blend that is very useful as a reference, the Microsoft Expression Blend® Add-in Preview for Windows® Phone. This will install a .extension.dll file in the extension folder of Blend. You can load this file with Reflector and have a peek at how Microsoft is building his addins. Conclusion I hope this gives you something to get started building extensions for Expression Blend. Until Microsoft releases the final version, which hopefully includes more information about building extensions, we’ll have to work on documenting it in the community.

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• Setup and Use SpecFlow BDD with DevExpress XAF

  - by Patrick Liekhus

  Let’s get started with using the SpecFlow BDD syntax for writing tests with the DevExpress XAF EasyTest scripting syntax.  In order for this to work you will need to download and install the prerequisites listed below.  Once they are installed follow the steps outlined below and enjoy. Prerequisites Install the following items: DevExpress eXpress Application Framework (XAF) found here SpecFlow found here Liekhus BDD/XAF Testing library found here Assumptions I am going to assume at this point that you have created your XAF application and have your Module, Win.Module and Win ready for usage.  You should have also set any attributes and/or settings as you see fit. Setup So where to start. Create a new testing project within your solution. I typically call this with a similar naming convention as used by XAF, my project name .FunctionalTests (i.e. AlbumManager.FunctionalTests). Add the following references to your project.  It should look like the reference list below. DevExpress.Data.v11.x DevExpress.Persistent.Base.v11.x DevExpress.Persistent.BaseImpl.v11.x DevExpress.Xpo.v11.2 Liekhus.Testing.BDD.Core Liekhus.Testing.BDD.DevExpress TechTalk.SpecFlow TestExecutor.v11.x (found in %Program Files%\DevExpress 2011.x\eXpressApp Framework\Tools\EasyTest Right click the TestExecutor reference and set the “Copy Local” setting to True.  This forces the TestExecutor executable to be available in the bin directory which is where the EasyTest script will be executed further down in the process. Add an Application Configuration File (app.config) to your test application.  You will need to make a few modifications to have SpecFlow generate Microsoft style unit tests.  First add the section handler for SpecFlow and then set your choice of testing framework.  I prefer MS Tests for my projects. Add the EasyTest configuration file to your project.  Add a new XML file and call it Config.xml. Open the properties window for the Config.xml file and set the “Copy to Ouput Directory” to “Copy Always”. You will setup the Config file according to the specifications of the EasyTest library my mapping to your executable and other settings.  You can find the details for the configuration of EasyTest here.  My file looks like this Create a new folder in your test project called “StepDefinitions”.  Add a new SpecFlow Step Definition file item under the StepDefinitions folder.  I typically call this class StepDefinition.cs. Have your step definition inherit from the Liekhus.Testing.BDD.DevExpress.StepDefinition class.  This will give you the default behaviors for your test in the next section. OK.  Now that we have done this series of steps, we will work on simplifying this.  This is an early preview of this new project and is not fully ready for consumption.  If you would like to experiment with it, please feel free.  Our goals are to make this a installable project on it’s own with it’s own project templates and default settings.  This will be coming in later versions.  Currently this project is in Alpha release. Let’s write our first test Remove the basic test that is created for you. We will not use the default test but rather create our own SpecFlow “Feature” files. Add a new item to your project and select the SpecFlow Feature file under C#. Name your feature file as you do your class files after the test they are performing. Writing a feature file uses the Cucumber syntax of Given… When… Then.  Think of it in these terms.  Givens are the pre-conditions for the test.  The Whens are the actual steps for the test being performed.  The Thens are the verification steps that confirm your test either passed or failed.  All of these steps are generated into a an EasyTest format and executed against your XAF project.  You can find more on the Cucumber syntax by using the Secret Ninja Cucumber Scrolls.  This document has several good styles of tests, plus you can get your fill of Chuck Norris vs Ninjas.  Pretty humorous document but full of great content. My first test is going to test the entry of a new Album into the application and is outlined below. The Feature section at the top is more for your documentation purposes.  Try to be descriptive of the test so that it makes sense to the next person behind you.  The Scenario outline is described in the Ninja Scrolls, but think of it as test template.  You can write one test outline and have multiple datasets (Scenarios) executed against that test.  Here are the steps of my test and their descriptions Given I am starting a new test – tells our test to create a new EasyTest file And (Given) the application is open – tells EasyTest to open our application defined in the Config.xml When I am at the “Albums” screen – tells XAF to navigate to the Albums list view And (When) I click the “New:Album” button – tells XAF to click the New Album button on the ribbon And (When) I enter the following information – tells XAF to find the field on the screen and put the value in that field And (When) I click the “Save and Close” button – tells XAF to click the “Save and Close” button on the detail window Then I verify results as “user” – tells the testing framework to execute the EasyTest as your configured user Once you compile and prepare your tests you should see the following in your Test View.  For each of your CreateNewAlbum lines in your scenarios, you will see a new test ready to execute. From here you will use your testing framework of choice to execute the test.  This in turn will execute the EasyTest framework to call back into your XAF application and test your business application. Again, please remember that this is an early preview and we are still working out the details.  Please let us know if you have any comments/questions/concerns. Thanks and happy testing.

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• A pseudo-listener for AlwaysOn Availability Groups for SQL Server virtual machines running in Azure

  - by MikeD

  I am involved in a project that is implementing SharePoint 2013 on virtual machines hosted in Azure. The back end data tier consists of two Azure VMs running SQL Server 2012, with the SharePoint databases contained in an AlwaysOn Availability Group. I used this "Tutorial: AlwaysOn Availability Groups in Windows Azure (GUI)" to help me implement this setup.Because Azure DHCP will not assign multiple unique IP addresses to the same VM, having an AG Listener in Azure is not currently supported.  I wanted to figure out another mechanism to support a "pseudo listener" of some sort. First, I created a CNAME (alias) record in the DNS zone with a short TTL (time to live) of 5 minutes (I may yet make this even shorter). The record represents a logical name (let's say the alias is SPSQL) of the server to connect to for the databases in the availability group (AG). When Server1 was hosting the primary replica of the AG, I would set the CNAME of SPSQL to be SERVER1. When the AG failed over to Server1, I wanted to set the CNAME to SERVER2. Seemed simple enough.(It's important to point out that the connection strings for my SharePoint services should use the CNAME alias, and not the actual server name. This whole thing falls apart otherwise.)To accomplish this, I created identical SQL Agent Jobs on Server1 and Server2, with two steps:1. Step 1: Determine if this server is hosting the primary replica.This is a TSQL step using this script:declare @agName sysname = 'AGTest'set nocount on declare @primaryReplica sysnameselect @primaryReplica = agState.primary_replicafrom sys.dm_hadr_availability_group_states agState   join sys.availability_groups ag on agstate.group_id = ag.group_id   where ag.name = @AGname if not exists(   select *    from sys.dm_hadr_availability_group_states agState   join sys.availability_groups ag on agstate.group_id = ag.group_id   where @@Servername = agstate.primary_replica    and ag.name = @AGname)begin   raiserror ('Primary replica of %s is not hosted on %s, it is hosted on %s',17,1,@Agname, @@Servername, @primaryReplica) endThis script determines if the primary replica value of the AG group is the same as the server name, which means that our server is hosting the current AG (you should update the value of the @AgName variable to the name of your AG). If this is true, I want the DNS alias to point to this server. If the current server is not hosting the primary replica, then the script raises an error. Also, if the script can't be executed because it cannot connect to the server, that also will generate an error. For the job step settings, I set the On Failure option to "Quit the job reporting success". The next step in the job will set the DNS alias to this server name, and I only want to do that if I know that it is the current primary replica, otherwise I don't want to do anything. I also include the step output in the job history so I can see the error message.Job Step 2: Update the CNAME entry in DNS with this server's name.I used a PowerShell script to accomplish this:$cname = "SPSQL.contoso.com"$query = "Select * from MicrosoftDNS_CNAMEType"$dns1 = "dc01.contoso.com"$dns2 = "dc02.contoso.com"if ((Test-Connection -ComputerName $dns1 -Count 1 -Quiet) -eq $true){    $dnsServer = $dns1}elseif ((Test-Connection -ComputerName $dns2 -Count 1 -Quiet) -eq $true) {   $dnsServer = $dns2}else{  $msg = "Unable to connect to DNS servers: " + $dns1 + ", " + $dns2   Throw $msg}$record = Get-WmiObject -Namespace "root\microsoftdns" -Query $query -ComputerName $dnsServer  | ? { $_.Ownername -match $cname }$thisServer = [System.Net.Dns]::GetHostEntry("LocalHost").HostName + "."$currentServer = $record.RecordData if ($currentServer -eq $thisServer ) {     $cname + " CNAME is up to date: " + $currentServer}else{    $cname + " CNAME is being updated to " + $thisServer + ". It was " + $currentServer    $record.RecordData = $thisServer    $record.put()}This script does a few things:finds a responsive domain controller (Test-Connection does a ping and returns a Boolean value if you specify the -Quiet parameter)makes a WMI call to the domain controller to get the current CNAME record value (Get-WmiObject)gets the FQDN of this server (GetHostEntry)checks if the CNAME record is correct and updates it if necessary(You should update the values of the variables $cname, $dns1 and $dns2 for your environment.)Since my domain controllers are also hosted in Azure VMs, either one of them could be down at any point in time, so I need to find a DC that is responsive before attempting the DNS call. The other little thing here is that the CNAME record contains the FQDN of a machine, plus it ends with a period. So the comparison of the CNAME record has to take the trailing period into account. When I tested this step, I was getting ACCESS DENIED responses from PowerShell for the Get-WmiObject cmdlet that does a remote lookup on the DC. This occurred because the SQL Agent service account was not a member of the Domain Admins group, so I decided to create a SQL Credential to store the credentials for a domain administrator account and use it as a PowerShell proxy (rather than give the service account Domain Admins membership).In SQL Management Studio, right click on the Credentials node (under the server's Security node), and choose New Credential...Then, under SQL Agent-->Proxies, right click on the PowerShell node and choose New Proxy...Finally, in the job step properties for the PowerShell step, select the new proxy in the Run As drop down.I created this two step Job on both nodes of the Availability Group, but if you had more than two nodes, just create the same job on all the servers. I set the schedule for the job to execute every minute.When the server that is hosting the primary replica is running the job, the job history looks like this:The job history on the secondary server looks like this: When a failover occurs, the SQL Agent job on the new primary replica will detect that the CNAME needs to be updated within a minute. Based on the TTL of the CNAME (which I said at the beginning was 5 minutes), the SharePoint servers will get the new alias within five minutes and should be able to reconnect. I may want to shorten up the TTL to reduce the time it takes for the client connections to use the new alias. Using a DNS CNAME and a SQL Agent Job on all servers hosting AG replicas, I was able to create a pseudo-listener to automatically change the name of the server that was hosting the primary replica, for a scenario where I cannot use a regular AG listener (in this case, because the servers are all hosted in Azure).    

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• How To - Guide to Importing Data from a MySQL Database to Excel using MySQL for Excel

  - by Javier Treviño

  Fetching data from a database to then get it into an Excel spreadsheet to do analysis, reporting, transforming, sharing, etc. is a very common task among users. There are several ways to extract data from a MySQL database to then import it to Excel; for example you can use the MySQL Connector/ODBC to configure an ODBC connection to a MySQL database, then in Excel use the Data Connection Wizard to select the database and table from which you want to extract data from, then specify what worksheet you want to put the data into.  Another way is to somehow dump a comma delimited text file with the data from a MySQL table (using the MySQL Command Line Client, MySQL Workbench, etc.) to then in Excel open the file using the Text Import Wizard to attempt to correctly split the data in columns. These methods are fine, but involve some degree of technical knowledge to make the magic happen and involve repeating several steps each time data needs to be imported from a MySQL table to an Excel spreadsheet. So, can this be done in an easier and faster way? With MySQL for Excel you can. MySQL for Excel features an Import MySQL Data action where you can import data from a MySQL Table, View or Stored Procedure literally with a few clicks within Excel.  Following is a quick guide describing how to import data using MySQL for Excel. This guide assumes you already have a working MySQL Server instance, Microsoft Office Excel 2007 or 2010 and MySQL for Excel installed. 1. Opening MySQL for Excel Being an Excel Add-In, MySQL for Excel is opened from within Excel, so to use it open Excel, go to the Data tab located in the Ribbon and click MySQL for Excel at the far right of the Ribbon. 2. Creating a MySQL Connection (may be optional) If you have MySQL Workbench installed you will automatically see the same connections that you can see in MySQL Workbench, so you can use any of those and there may be no need to create a new connection. If you want to create a new connection (which normally you will do only once), in the Welcome Panel click New Connection, which opens the Setup New Connection dialog. Here you only need to give your new connection a distinctive Connection Name, specify the Hostname (or IP address) where the MySQL Server instance is running on (if different than localhost), the Port to connect to and the Username for the login. If you wish to test if your setup is good to go, click Test Connection and an information dialog will pop-up stating if the connection is successful or errors were found. 3.Opening a connection to a MySQL Server To open a pre-configured connection to a MySQL Server you just need to double-click it, so the Connection Password dialog is displayed where you enter the password for the login. 4. Selecting a MySQL Schema After opening a connection to a MySQL Server, the Schema Selection Panel is shown, where you can select the Schema that contains the Tables, Views and Stored Procedures you want to work with. To do so, you just need to either double-click the desired Schema or select it and click Next >. 5. Importing data… All previous steps were really the basic minimum needed to drill-down to the DB Object Selection Panel  where you can see the Database Objects (grouped by type: Tables, Views and Procedures in that order) that you want to perform actions against; in the case of this guide, the action of importing data from them. a. From a MySQL Table To import from a Table you just need to select it from the list of Database Objects’ Tables group, after selecting it you will note actions below the list become available; then click Import MySQL Data. The Import Data dialog is displayed; you can see some basic information here like the name of the Excel worksheet the data will be imported to (in the window title), the Table Name, the total Row Count and a 10 row preview of the data meant for the user to see the columns that the table contains and to provide a way to select which columns to import. The Import Data dialog is designed with defaults in place so all data is imported (all rows and all columns) by just clicking Import; this is important to minimize the number of clicks needed to get the job done. After the import is performed you will have the data in the Excel worksheet formatted automatically. If you need to override the defaults in the Import Data dialog to change the columns selected for import or to change the number of imported rows you can easily do so before clicking Import. In the screenshot below the defaults are overridden to import only the first 3 columns and rows 10 – 60 (Limit to 50 Rows and Start with Row 10). If the number of rows to be imported exceeds the maximum number of rows Excel can hold in its worksheet, a warning will be displayed in the dialog, meaning the imported number of rows will be limited by that maximum number (65,535 rows if the worksheet is in Compatibility Mode).  In the screenshot below you can see the Table contains 80,559 rows, but only 65,534 rows will be imported since the first row is used for the column names if the Include Column Names as Headers checkbox is checked. b. From a MySQL View Similar to the way of importing from a Table, to import from a View you just need to select it from the list of Database Objects’ Views group, then click Import MySQL Data. The Import Data dialog is displayed; identically to the way everything looks when importing from a table, the dialog displays the View Name, the total Row Count and the data preview grid. Since Views are really a filtered way to display data from Tables, it is actually as if we are extracting data from a Table; so the Import Data dialog is actually identical for those 2 Database Objects. After the import is performed, the data in the Excel spreadsheet looks like the following screenshot. Note that you can override the defaults in the Import Data dialog in the same way described above for importing data from Tables. Also the Compatibility Mode warning will be displayed if data exceeds the maximum number of rows explained before. c. From a MySQL Procedure Too import from a Procedure you just need to select it from the list of Database Objects’ Procedures group (note you can see Procedures here but not Functions since these return a single value, so by design they are filtered out). After the selection is made, click Import MySQL Data. The Import Data dialog is displayed, but this time you can see it looks different to the one used for Tables and Views.  Given the nature of Store Procedures, they require first that values are supplied for its Parameters and also Procedures can return multiple Result Sets; so the Import Data dialog shows the Procedure Name and the Procedure Parameters in a grid where their values are input. After you supply the Parameter Values click Call. After calling the Procedure, the Result Sets returned by it are displayed at the bottom of the dialog; output parameters and the return value of the Procedure are appended as the last Result Set of the group. You can see each Result Set is displayed as a tab so you can see a preview of the returned data.  You can specify if you want to import the Selected Result Set (default), All Result Sets – Arranged Horizontally or All Result Sets – Arranged Vertically using the Import drop-down list; then click Import. After the import is performed, the data in the Excel spreadsheet looks like the following screenshot.  Note in this example all Result Sets were imported and arranged vertically. As you can see using MySQL for Excel importing data from a MySQL database becomes an easy task that requires very little technical knowledge, so it can be done by any type of user. Hope you enjoyed this guide! Remember that your feedback is very important for us, so drop us a message: MySQL on Windows (this) Blog - https://blogs.oracle.com/MySqlOnWindows/ Forum - http://forums.mysql.com/list.php?172 Facebook - http://www.facebook.com/mysql Cheers!

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• A simple Dynamic Proxy

  - by Abhijeet Patel

  Frameworks such as EF4 and MOQ do what most developers consider "dark magic". For instance in EF4, when you use a POCO for an entity you can opt-in to get behaviors such as "lazy-loading" and "change tracking" at runtime merely by ensuring that your type has the following characteristics: The class must be public and not sealed. The class must have a public or protected parameter-less constructor. The class must have public or protected properties Adhere to this and your type is magically endowed with these behaviors without any additional programming on your part. Behind the scenes the framework subclasses your type at runtime and creates a "dynamic proxy" which has these additional behaviors and when you navigate properties of your POCO, the framework replaces the POCO type with derived type instances. The MOQ framework does simlar magic. Let's say you have a simple interface:   public interface IFoo      {          int GetNum();      }   We can verify that the GetNum() was invoked on a mock like so:   var mock = new Mock<IFoo>(MockBehavior.Default);   mock.Setup(f => f.GetNum());   var num = mock.Object.GetNum();   mock.Verify(f => f.GetNum());   Beind the scenes the MOQ framework is generating a dynamic proxy by implementing IFoo at runtime. the call to moq.Object returns the dynamic proxy on which we then call "GetNum" and then verify that this method was invoked. No dark magic at all, just clever programming is what's going on here, just not visible and hence appears magical! Let's create a simple dynamic proxy generator which accepts an interface type and dynamically creates a proxy implementing the interface type specified at runtime.     public static class DynamicProxyGenerator   {       public static T GetInstanceFor<T>()       {           Type typeOfT = typeof(T);           var methodInfos = typeOfT.GetMethods();           AssemblyName assName = new AssemblyName("testAssembly");           var assBuilder = AppDomain.CurrentDomain.DefineDynamicAssembly(assName, AssemblyBuilderAccess.RunAndSave);           var moduleBuilder = assBuilder.DefineDynamicModule("testModule", "test.dll");           var typeBuilder = moduleBuilder.DefineType(typeOfT.Name + "Proxy", TypeAttributes.Public);              typeBuilder.AddInterfaceImplementation(typeOfT);           var ctorBuilder = typeBuilder.DefineConstructor(                     MethodAttributes.Public,                     CallingConventions.Standard,                     new Type[] { });           var ilGenerator = ctorBuilder.GetILGenerator();           ilGenerator.EmitWriteLine("Creating Proxy instance");           ilGenerator.Emit(OpCodes.Ret);           foreach (var methodInfo in methodInfos)           {               var methodBuilder = typeBuilder.DefineMethod(                   methodInfo.Name,                   MethodAttributes.Public | MethodAttributes.Virtual,                   methodInfo.ReturnType,                   methodInfo.GetParameters().Select(p => p.GetType()).ToArray()                   );               var methodILGen = methodBuilder.GetILGenerator();               methodILGen.EmitWriteLine("I'm a proxy");               if (methodInfo.ReturnType == typeof(void))               {                   methodILGen.Emit(OpCodes.Ret);               }               else               {                   if (methodInfo.ReturnType.IsValueType || methodInfo.ReturnType.IsEnum)                   {                       MethodInfo getMethod = typeof(Activator).GetMethod(/span>"CreateInstance",new Type[]{typeof((Type)});                                               LocalBuilder lb = methodILGen.DeclareLocal(methodInfo.ReturnType);                       methodILGen.Emit(OpCodes.Ldtoken, lb.LocalType);                       methodILGen.Emit(OpCodes.Call, typeofype).GetMethod("GetTypeFromHandle"));  ));                       methodILGen.Emit(OpCodes.Callvirt, getMethod);                       methodILGen.Emit(OpCodes.Unbox_Any, lb.LocalType);                                                              }                 else                   {                       methodILGen.Emit(OpCodes.Ldnull);                   }                   methodILGen.Emit(OpCodes.Ret);               }               typeBuilder.DefineMethodOverride(methodBuilder, methodInfo);           }                     Type constructedType = typeBuilder.CreateType();           var instance = Activator.CreateInstance(constructedType);           return (T)instance;       }   }   Dynamic proxies are created by calling into the following main types: AssemblyBuilder, TypeBuilder, Modulebuilder and ILGenerator. These types enable dynamically creating an assembly and emitting .NET modules and types in that assembly, all using IL instructions. Let's break down the code above a bit and examine it piece by piece                Type typeOfT = typeof(T);              var methodInfos = typeOfT.GetMethods();              AssemblyName assName = new AssemblyName("testAssembly");              var assBuilder = AppDomain.CurrentDomain.DefineDynamicAssembly(assName, AssemblyBuilderAccess.RunAndSave);              var moduleBuilder = assBuilder.DefineDynamicModule("testModule", "test.dll");              var typeBuilder = moduleBuilder.DefineType(typeOfT.Name + "Proxy", TypeAttributes.Public);   We are instructing the runtime to create an assembly caled "test.dll"and in this assembly we then emit a new module called "testModule". We then emit a new type definition of name "typeName"Proxy into this new module. This is the definition for the "dynamic proxy" for type T                 typeBuilder.AddInterfaceImplementation(typeOfT);               var ctorBuilder = typeBuilder.DefineConstructor(                         MethodAttributes.Public,                         CallingConventions.Standard,                         new Type[] { });               var ilGenerator = ctorBuilder.GetILGenerator();               ilGenerator.EmitWriteLine("Creating Proxy instance");               ilGenerator.Emit(OpCodes.Ret);   The newly created type implements type T and defines a default parameterless constructor in which we emit a call to Console.WriteLine. This call is not necessary but we do this so that we can see first hand that when the proxy is constructed, when our default constructor is invoked.   var methodBuilder = typeBuilder.DefineMethod(                      methodInfo.Name,                      MethodAttributes.Public | MethodAttributes.Virtual,                      methodInfo.ReturnType,                      methodInfo.GetParameters().Select(p => p.GetType()).ToArray()                      );   We then iterate over each method declared on type T and add a method definition of the same name into our "dynamic proxy" definition     if (methodInfo.ReturnType == typeof(void))   {       methodILGen.Emit(OpCodes.Ret);   }   If the return type specified in the method declaration of T is void we simply return.     if (methodInfo.ReturnType.IsValueType || methodInfo.ReturnType.IsEnum)   {                               MethodInfo getMethod = typeof(Activator).GetMethod("CreateInstance",                                                         new Type[]{typeof(Type)});                               LocalBuilder lb = methodILGen.DeclareLocal(methodInfo.ReturnType);                                                     methodILGen.Emit(OpCodes.Ldtoken, lb.LocalType);       methodILGen.Emit(OpCodes.Call, typeof(Type).GetMethod("GetTypeFromHandle"));       methodILGen.Emit(OpCodes.Callvirt, getMethod);       methodILGen.Emit(OpCodes.Unbox_Any, lb.LocalType);   }   If the return type in the method declaration of T is either a value type or an enum, then we need to create an instance of the value type and return that instance the caller. In order to accomplish that we need to do the following: 1) Get a handle to the Activator.CreateInstance method 2) Declare a local variable which represents the Type of the return type(i.e the type object of the return type) specified on the method declaration of T(obtained from the MethodInfo) and push this Type object onto the evaluation stack. In reality a RuntimeTypeHandle is what is pushed onto the stack. 3) Invoke the "GetTypeFromHandle" method(a static method in the Type class) passing in the RuntimeTypeHandle pushed onto the stack previously as an argument, the result of this invocation is a Type object (representing the method's return type) which is pushed onto the top of the evaluation stack. 4) Invoke Activator.CreateInstance passing in the Type object from step 3, the result of this invocation is an instance of the value type boxed as a reference type and pushed onto the top of the evaluation stack. 5) Unbox the result and place it into the local variable of the return type defined in step 2   methodILGen.Emit(OpCodes.Ldnull);   If the return type is a reference type then we just load a null onto the evaluation stack   methodILGen.Emit(OpCodes.Ret);   Emit a a return statement to return whatever is on top of the evaluation stack(null or an instance of a value type) back to the caller     Type constructedType = typeBuilder.CreateType();   var instance = Activator.CreateInstance(constructedType);   return (T)instance;   Now that we have a definition of the "dynamic proxy" implementing all the methods declared on T, we can now create an instance of the proxy type and return that out typed as T. The caller can now invoke the generator and request a dynamic proxy for any type T. In our example when the client invokes GetNum() we get back "0". Lets add a new method on the interface called DayOfWeek GetDay()   public interface IFoo      {          int GetNum();          DayOfWeek GetDay();      }   When GetDay() is invoked, the "dynamic proxy" returns "Sunday" since that is the default value for the DayOfWeek enum This is a very trivial example of dynammic proxies, frameworks like MOQ have a way more sophisticated implementation of this paradigm where in you can instruct the framework to create proxies which return specified values for a method implementation.

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• Updating a SharePoint master page via a solution (WSP)

  - by Kelly Jones

  In my last blog post, I wrote how to deploy a SharePoint theme using Features and a solution package.  As promised in that post, here is how to update an already deployed master page. There are several ways to update a master page in SharePoint.  You could upload a new version to the master page gallery, or you could upload a new master page to the gallery, and then set the site to use this new page.  Manually uploading your master page to the master page gallery might be the best option, depending on your environment.  For my client, I did these steps in code, which is what they preferred. (Image courtesy of: http://www.joiningdots.net/blog/2007/08/sharepoint-and-quick-launch.html ) Before you decide which method you need to use, take a look at your existing pages.  Are they using the SharePoint dynamic token or the static token for the master page reference?  The wha, huh? SO, there are four ways to tell an .aspx page hosted in SharePoint which master page it should use: “~masterurl/default.master” – tells the page to use the default.master property of the site “~masterurl/custom.master” – tells the page to use the custom.master property of the site “~site/default.master” – tells the page to use the file named “default.master” in the site’s master page gallery “~sitecollection/default.master” – tells the page to use the file named “default.master” in the site collection’s master page gallery For more information about these tokens, take a look at this article on MSDN. Once you determine which token your existing pages are pointed to, then you know which file you need to update.  So, if the ~masterurl tokens are used, then you upload a new master page, either replacing the existing one or adding another one to the gallery.  If you’ve uploaded a new file with a new name, you’ll just need to set it as the master page either through the UI (MOSS only) or through code (MOSS or WSS Feature receiver code – or using SharePoint Designer). If the ~site or ~sitecollection tokens were used, then you’re limited to either replacing the existing master page, or editing all of your existing pages to point to another master page.  In most cases, it probably makes sense to just replace the master page. For my project, I’m working with WSS and the existing pages are set to the ~sitecollection token.  Based on this, I decided to just upload a new version of the existing master page (and not modify the dozens of existing pages). Also, since my client prefers Features and solutions, I created a master page Feature and a corresponding Feature Receiver.  For information on creating the elements and feature files, check out this post: http://sharepointmagazine.net/technical/development/deploying-the-master-page . This works fine, unless you are overwriting an existing master page, which was my case.  You’ll run into errors because the master page file needs to be checked out, replaced, and then checked in.  I wrote code in my Feature Activated event handler to accomplish these steps. Here are the steps necessary in code: Get the file name from the elements file of the Feature Check out the file from the master page gallery Upload the file to the master page gallery Check in the file to the master page gallery Here’s the code in my Feature Receiver: 1: public override void FeatureActivated(SPFeatureReceiverProperties properties) 2: { 3: try 4: { 5:   6: SPElementDefinitionCollection col = properties.Definition.GetElementDefinitions(System.Globalization.CultureInfo.CurrentCulture); 7:   8: using (SPWeb curweb = GetCurWeb(properties)) 9: { 10: foreach (SPElementDefinition ele in col) 11: { 12: if (string.Compare(ele.ElementType, "Module", true) == 0) 13: { 14: // <Module Name="DefaultMasterPage" List="116" Url="_catalogs/masterpage" RootWebOnly="FALSE"> 15: // <File Url="myMaster.master" Type="GhostableInLibrary" IgnoreIfAlreadyExists="TRUE" 16: // Path="MasterPages/myMaster.master" /> 17: // </Module> 18: string Url = ele.XmlDefinition.Attributes["Url"].Value; 19: foreach (System.Xml.XmlNode file in ele.XmlDefinition.ChildNodes) 20: { 21: string Url2 = file.Attributes["Url"].Value; 22: string Path = file.Attributes["Path"].Value; 23: string fileType = file.Attributes["Type"].Value; 24:   25: if (string.Compare(fileType, "GhostableInLibrary", true) == 0) 26: { 27: //Check out file in document library 28: SPFile existingFile = curweb.GetFile(Url + "/" + Url2); 29:   30: if (existingFile != null) 31: { 32: if (existingFile.CheckOutStatus != SPFile.SPCheckOutStatus.None) 33: { 34: throw new Exception("The master page file is already checked out. Please make sure the master page file is checked in, before activating this feature."); 35: } 36: else 37: { 38: existingFile.CheckOut(); 39: existingFile.Update(); 40: } 41: } 42:   43: //Upload file to document library 44: string filePath = System.IO.Path.Combine(properties.Definition.RootDirectory, Path); 45: string fileName = System.IO.Path.GetFileName(filePath); 46: char slash = Convert.ToChar("/"); 47: string[] folders = existingFile.ParentFolder.Url.Split(slash); 48:   49: if (folders.Length > 2) 50: { 51: Logger.logMessage("More than two folders were detected in the library path for the master page. Only two are supported.", 52: Logger.LogEntryType.Information); //custom logging component 53: } 54:   55: SPFolder myLibrary = curweb.Folders[folders[0]].SubFolders[folders[1]]; 56:   57: FileStream fs = File.OpenRead(filePath); 58:   59: SPFile newFile = myLibrary.Files.Add(fileName, fs, true); 60:   61: myLibrary.Update(); 62: newFile.CheckIn("Updated by Feature", SPCheckinType.MajorCheckIn); 63: newFile.Update(); 64: } 65: } 66: } 67: } 68: } 69: } 70: catch (Exception ex) 71: { 72: string msg = "Error occurred during feature activation"; 73: Logger.logException(ex, msg, ""); 74: } 75:   76: } 77:   78: /// <summary> 79: /// Using a Feature's properties, get a reference to the Current Web 80: /// </summary> 81: /// <param name="properties"></param> 82: public SPWeb GetCurWeb(SPFeatureReceiverProperties properties) 83: { 84: SPWeb curweb; 85:   86: //Check if the parent of the web is a site or a web 87: if (properties != null && properties.Feature.Parent.GetType().ToString() == "Microsoft.SharePoint.SPWeb") 88: { 89:   90: //Get web from parent 91: curweb = (SPWeb)properties.Feature.Parent; 92: 93: } 94: else 95: { 96: //Get web from Site 97: using (SPSite cursite = (SPSite)properties.Feature.Parent) 98: { 99: curweb = (SPWeb)cursite.OpenWeb(); 100: } 101: } 102:   103: return curweb; 104: } This did the trick.  It allowed me to update my existing master page, through an easily repeatable process (which is great when you are working with more than one environment and what to do things like TEST it!).  I did run into what I would classify as a strange issue with one of my subsites, but that’s the topic for another blog post.

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• Dynamic Code for type casting Generic Types 'generically' in C#

  - by Rick Strahl

  C# is a strongly typed language and while that's a fundamental feature of the language there are more and more situations where dynamic types make a lot of sense. I've written quite a bit about how I use dynamic for creating new type extensions: Dynamic Types and DynamicObject References in C# Creating a dynamic, extensible C# Expando Object Creating a dynamic DataReader for dynamic Property Access Today I want to point out an example of a much simpler usage for dynamic that I use occasionally to get around potential static typing issues in C# code especially those concerning generic types. TypeCasting Generics Generic types have been around since .NET 2.0 I've run into a number of situations in the past - especially with generic types that don't implement specific interfaces that can be cast to - where I've been unable to properly cast an object when it's passed to a method or assigned to a property. Granted often this can be a sign of bad design, but in at least some situations the code that needs to be integrated is not under my control so I have to make due with what's available or the parent object is too complex or intermingled to be easily refactored to a new usage scenario. Here's an example that I ran into in my own RazorHosting library - so I have really no excuse, but I also don't see another clean way around it in this case. A Generic Example Imagine I've implemented a generic type like this: public class RazorEngine<TBaseTemplateType> where TBaseTemplateType : RazorTemplateBase, new() You can now happily instantiate new generic versions of this type with custom template bases or even a non-generic version which is implemented like this: public class RazorEngine : RazorEngine<RazorTemplateBase> { public RazorEngine() : base() { } } To instantiate one: var engine = new RazorEngine<MyCustomRazorTemplate>(); Now imagine that the template class receives a reference to the engine when it's instantiated. This code is fired as part of the Engine pipeline when it gets ready to execute the template. It instantiates the template and assigns itself to the template: var template = new TBaseTemplateType() { Engine = this } The problem here is that possibly many variations of RazorEngine<T> can be passed. I can have RazorTemplateBase, RazorFolderHostTemplateBase, CustomRazorTemplateBase etc. as generic parameters and the Engine property has to reflect that somehow. So, how would I cast that? My first inclination was to use an interface on the engine class and then cast to the interface.  Generally that works, but unfortunately here the engine class is generic and has a few members that require the template type in the member signatures. So while I certainly can implement an interface: public interface IRazorEngine<TBaseTemplateType> it doesn't really help for passing this generically templated object to the template class - I still can't cast it if multiple differently typed versions of the generic type could be passed. I have the exact same issue in that I can't specify a 'generic' generic parameter, since there's no underlying base type that's common. In light of this I decided on using object and the following syntax for the property (and the same would be true for a method parameter): public class RazorTemplateBase :MarshalByRefObject,IDisposable { public object Engine {get;set; } } Now because the Engine property is a non-typed object, when I need to do something with this value, I still have no way to cast it explicitly. What I really would need is: public RazorEngine<> Engine { get; set; } but that's not possible. Dynamic to the Rescue Luckily with the dynamic type this sort of thing can be mitigated fairly easily. For example here's a method that uses the Engine property and uses the well known class interface by simply casting the plain object reference to dynamic and then firing away on the properties and methods of the base template class that are common to all templates:/// <summary> /// Allows rendering a dynamic template from a string template /// passing in a model. This is like rendering a partial /// but providing the input as a /// </summary> public virtual string RenderTemplate(string template,object model) { if (template == null) return string.Empty; // if there's no template markup if(!template.Contains("@")) return template; // use dynamic to get around generic type casting dynamic engine = Engine; string result = engine.RenderTemplate(template, model); if (result == null) throw new ApplicationException("RenderTemplate failed: " + engine.ErrorMessage); return result; } Prior to .NET 4.0  I would have had to use Reflection for this sort of thing which would have a been a heck of a lot more verbose, but dynamic makes this so much easier and cleaner and in this case at least the overhead is negliable since it's a single dynamic operation on an otherwise very complex operation call. Dynamic as  a Bailout Sometimes this sort of thing often reeks of a design flaw, and I agree that in hindsight this could have been designed differently. But as is often the case this particular scenario wasn't planned for originally and removing the generic signatures from the base type would break a ton of other code in the framework. Given the existing fairly complex engine design, refactoring an interface to remove generic types just to make this particular code work would have been overkill. Instead dynamic provides a nice and simple and relatively clean solution. Now if there were many other places where this occurs I would probably consider reworking the code to make this cleaner but given this isolated instance and relatively low profile operation use of dynamic seems a valid choice for me. This solution really works anywhere where you might end up with an inheritance structure that doesn't have a common base or interface that is sufficient. In the example above I know what I'm getting but there's no common base type that I can cast to. All that said, it's a good idea to think about use of dynamic before you rush in. In many situations there are alternatives that can still work with static typing. Dynamic definitely has some overhead compared to direct static access of objects, so if possible we should definitely stick to static typing. In the example above the application already uses dynamics extensively for dynamic page page templating and passing models around so introducing dynamics here has very little additional overhead. The operation itself also fires of a fairly resource heavy operation where the overhead of a couple of dynamic member accesses are not a performance issue. So, what's your experience with dynamic as a bailout mechanism? © Rick Strahl, West Wind Technologies, 2005-2012Posted in CSharp   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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